Particle beam system and method for operating a particle beam system

Abstract

Particle beam system (1, 1a, 1b), comprising: a stage (55) for receiving a holder (27, 27a, 27b) with an object (29) held on it, wherein a first temperature sensor (57) is attached to the stage (55); a particle beam source (63) for generating a particle beam (65) directed at the object (29); a vacuum jacket (11) that defines a vacuum space (17) in which at least the object stage (55) is arranged; a lock (5, 5a) coupled to the vacuum chamber (17) with a lock chamber (7, 7a) which is separated from the vacuum chamber (17) by an openable door (15); and a transfer device (35, 35a, 35b) for transporting the object holder (27, 27a, 27b) from the airlock (5, 5a) to the object table (55); 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) which is attached to one end of the rod (35, 35a, 35b) and which is 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 coupling (38, 38a, 38b); and a supply line (47, 47a, 47b) for a heater (41, 41a, 41b) which leads to the coupling (38, 38a, 38b).

Description

[0001] The present invention relates to a particle beam system and a method for operating a particle beam system.

[0002] Particle beam systems, such as electron beam microscopes, feature a vacuum created within a vacuum chamber to minimize interactions between the particle beam and the atmosphere. To examine an object with the particle beam, the object is mounted on a specimen holder, which is then moved through an airlock into the vacuum chamber and positioned on a stage within the vacuum chamber, ensuring the object is in the path of the particle beam. The stage is equipped with an actuator to move the object relative to the particle beam. Operation of the actuator typically heats the stage. The specimen holder, however, maintains a room temperature outside the particle beam system, which differs from the temperature of the stage.When the object holder is placed on the stage, heat transfer occurs between the stage and the object holder, leading to thermal drift that interferes with the examination of the object.

[0003] To reduce such thermal drift, US patent 11,264,203 B1 proposes a method in which the object is first tempered and then passed through the airlock and positioned on the stage. However, when performing this method, a user of the particle beam system finds that the time required to position the object holder on the stage increases and that thermal drift is not completely prevented.

[0004] US Patent 2021 / 0156457A1 discloses an actuator for positioning an object, wherein the actuator is designed in such a way that it expands less in a positioning direction due to the application of heat.

[0005] US patent 2023 / 0184696A1 discloses a method for operating a particle beam system, wherein the method reduces thermal drift using software.

[0006] US patent 2023 / 0204525A1 discloses a particle beam system with a microscope slide and a stage, wherein the microscope slide can be detachably electrically coupled to the stage.

[0007] To solve the above problem, a particle beam system is proposed, comprising a stage for holding an object holder with an object attached to it, a first temperature sensor mounted on the stage, and a particle beam source for generating a particle beam directed at the object. It should be noted that the particle beam may not be directed at the object if the object is not mounted on the stage. Accordingly, the above refers to the operation of the particle beam system in which the object holder and the object are mounted on the stage.Furthermore, the particle beam system comprises a vacuum jacket that delimits a vacuum space in which at least the object stage is arranged, an airlock coupled to the vacuum space with an airlock room that is separated from the vacuum space by an openable door, and a transfer device for transporting the object holder from the airlock to the object stage.

[0008] The transfer device comprises an elongated rod penetrating a vacuum seal located in the vacuum jacket or wall of the airlock, and a coupling attached to one end of the rod, configured to be mechanically and detachably coupled to the specimen holder. In other words, the specimen holder can be attached to the rod via the coupling and then, along with the rod, slid through the airlock's opening door onto the specimen stage of the particle beam system. The coupling may, for example, include a threaded section that can be screwed into a threaded hole in the specimen holder for coupling.

[0009] The transfer device further comprises a signal line for a second temperature sensor, which is routed to the coupling, and a power supply line for a heater, also routed to the coupling. This signal and power supply line makes it possible to provide a temperature sensor and a heater with which the object and the object holder can be heated while they are being transferred with the rod through the openable door of the airlock. Heating during the transfer of the object holder eliminates the need to preheat the holder, thus reducing the time required to position the object holder on the stage compared to the prior art described above.

[0010] Furthermore, when heating the object holder while it is on a support in the airlock before the transfer begins, heat continuously flows into the support. This results in insufficient heating accuracy. The particle beam system disclosed herein solves this problem by coupling the object holder to the rod during a transfer and keeping it out of contact with other components of the particle beam system. This minimizes heat loss from the object holder, thereby increasing the accuracy and efficiency of the heating process.

[0011] Furthermore, the proposed particle beam system makes it possible to decouple at least the signal line and the power supply line. This prevents the rod, for example, from having to follow a movement of the stage when the object is positioned relative to the particle beam, which can lead to excessive stress in the vacuum feedthrough.

[0012] It should also be noted that the heating element here refers to a device suitable for temperature control of the object holder, i.e., for changing the temperature of the object holder. Accordingly, the heating element may, for example, include a cooling function with which the object holder can be cooled. Furthermore, the object holder itself is not necessarily enclosed by the particle beam system, but it may be enclosed by the particle beam system.

[0013] Examples of particle beam systems are systems in which an object is introduced into a vacuum chamber and positioned on a movable stage for examination, processing, and the like. In particular, such particle beam systems include electron beam microscopes, ion beam systems, lithography equipment, additive manufacturing devices, and the like.

[0014] According to some embodiments, the second temperature sensor can be attached to the coupling and connected directly to the signal line. However, according to alternative embodiments, the second temperature sensor can also be attached to the object holder, with a first electrical connector attached to the coupling being connected to the signal line and configured for detachable connection to a second electrical connector attached to the object holder, to which the second temperature sensor is connected. For example, the first electrical connector and the second electrical connector can form a sliding contact through which the second temperature sensor is connected to the signal line.

[0015] According to some embodiments, the heater can be attached to the coupling and connected directly to the supply line. However, according to alternative embodiments, the heater can also be attached to the object holder, with a first supply line connector attached to the coupling being connected to the supply line and configured for detachable connection to a second supply line connector attached to the object holder, to which the heater is connected. For example, the heater can be a heating element and / or a Peltier element and can be attached to either the coupling or the object holder. In such a case, the supply line can be an electrical conductor, and the heater can be connected to the supply line via a sliding contact, similar to the second temperature sensor described above.For example, the heating system can also be operated with a coolant that circulates in a cooling circuit, allowing switching between heating and cooling modes. In such a case, the supply line can be a coolant line through which the coolant flows.

[0016] According to some embodiments, the particle beam system further comprises a controller connected to the signal line and the power supply line, configured to control power supplied to the power supply line based on an output from the first temperature sensor and a signal received via the signal line. For example, the controller receives a measured temperature from the second temperature sensor via the signal line and supplies power to the heater that depends on the measured temperature. The power supplied to the heater is a quantity corresponding to the heater's power output, such as an electric current, an electric voltage, a coolant flow rate through the power supply line, or the like.For example, the power supplied by the controller can be adjusted so that the temperature measured by the second temperature sensor equals the temperature of the specimen table measured by the first temperature sensor when the specimen holder reaches the specimen table. The controller can be configured to supply a pulse-width modulated electrical current to the heater.

[0017] In 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 feedthrough is provided through the wall of the lock through which the signal line and / or the supply line are routed. In alternative embodiments, the signal line and / or the supply line is routed inside the rod to the coupling. This can be advantageous because no additional feedthrough through the vacuum jacket is required for the signal line and / or the supply line.

[0018] According to some embodiments, the particle beam system further comprises a support arranged within the airlock on which the object holder can rest when positioned within the airlock. For example, the support may include a fastening element to which the object holder can be temporarily attached while the rod is coupled to the object holder. The fastening element may be a clamping element that prevents the object holder from slipping when the rod is coupled to the holder.

[0019] According to some embodiments, the object holder is supported only by the rod when it is in a transfer position between the support and the stage. In a case where the rod is attached to one side of the object holder via a thread, the object holder hangs suspended from the rod when the object holder has already been transferred to the point where it is no longer supported by the support, and when the object holder has not yet been pushed all the way onto the stage.

[0020] 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 airlock 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 position by sliding the rod.

[0021] Furthermore, the procedure includes transferring the specimen holder from the airlock to the specimen stage of the particle beam system by actuating the transfer device and releasing the transfer device from the specimen holder. These steps allow the specimen holder to be placed on the specimen stage. The transfer process involves measuring the temperature of the specimen stage, moving the specimen holder away from the support, and heating or cooling the specimen holder after it has left the support. Heating or cooling the specimen holder after it has left the support saves time that would otherwise be required if the specimen holder were heated only before the transfer. Moving the specimen holder away from the support can be achieved, for example, by pushing the rod towards the specimen stage. The specimen holder has left the support when it is no longer in contact with it.In particular, the object holder has left the support if the 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 the distance between an end of the object table facing the support and an end of the support facing the object table.

[0022] The method further includes positioning the object by actuating the stage and scanning the object with the particle beam. For example, the object can be positioned using an actuator attached to the stage, which can adjust the height and / or lateral position of the stage perpendicular to the path of the particle beam.

[0023] Using the particle beam system operating method described above, it is possible to heat the object holder after it has left the support. As already described above, this improves heating efficiency because the heat supplied during heating cannot dissipate excessively into the support during the transfer.

[0024] According to some embodiments, heating or cooling includes measuring the temperature of the object holder. Furthermore, heating or cooling may also include supplying heating or cooling power to the object holder and determining the heating or cooling power based on the measured temperature of the object holder. As described above, the supplied heating or 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 or cooling power is also determined based on the measured temperature of the object stage. The heating or cooling power can be determined such that the temperature of the object holder at least approximates the temperature of the object stage. Preferably, the heating or cooling power can be determined by measuring the temperature of the object stage.The cooling capacity can also be determined in such a way that the temperature of the object holder is equalized to the temperature of the object stage before the object is scanned with the particle beam.

[0025] In some embodiments, heating comprises supplying a heating current to a heating resistor, wherein the heating resistor is attached to the object holder or to the coupling mounted on the transfer device. In some embodiments, cooling comprises supplying a current to a Peltier element, wherein the Peltier element is attached to the object holder or to a coupling mounted on the transfer device. In some embodiments, heating or cooling comprises passing a medium through the object holder or through a coupling mounted on the transfer device.

[0026] According to some embodiments, the method further comprises closing a door between a vacuum chamber in which the specimen table is located, before the specimen holder is placed on the support in the airlock, and opening the door before transferring the specimen holder from the airlock to the specimen table. Closing the door ensures that the vacuum in the vacuum chamber is not compromised when the specimen holder is placed on the support in the airlock. It can also be advantageous for the door to be open for the shortest possible time, such as only during the transfer of the specimen holder from the airlock to the specimen table and the retraction of the transfer device through the door.

[0027] According to some embodiments, scanning the object with the particle beam also includes generating an image of the object. For this purpose, signals generated by the object upon impact of the particle beam are, for example, detected by a detector and assigned to a deflection angle of the particle beam during scanning the object. The corresponding signals can then be displayed, for example, as an image on a screen.

[0028] The embodiments of the invention are explained in more detail below with reference to figures. Fig. Figure 1 shows a schematic view of a particle beam system according to one embodiment. Fig. Figure 2 shows a top view inside a lock chamber of the in Fig. 1 particle beam system shown. Fig. Figure 3 shows a cross-section of the lock chamber of a particle beam system according to a further embodiment. Fig. Figure 4 shows a schematic view of a coupling of a transfer device of a particle beam system according to a further embodiment. Fig. Figure 5 shows a flowchart of a procedure for operating the in Fig. 1 particle beam system shown according to one embodiment.

[0029] Fig. Figure 1 shows a schematic view of a particle beam system 1 according to one embodiment. The particle beam system 1 comprises a main body 3 and a lock 5. The particle beam system 1 can be, for example, an electron beam microscope, a lithography device, an additive manufacturing system, or the like.

[0030] The airlock 5 comprises an airlock chamber 7, which is bounded by an airlock wall 9 and part of a vacuum jacket 11 of the main body 3. The airlock wall 9 is rigidly connected to the vacuum jacket 11 of the main body 3. The airlock wall 9 has a pump port 13 to which a pump (not shown) is connected, which can generate a vacuum in the airlock chamber 7. The airlock chamber 9 is connected to a vacuum chamber 17 of the main body via an airlock door 15. The airlock door 15 is connected to an actuator 16, which can be operated to open and close the airlock 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 airlock door 15.The vacuum chamber 17 of the main body 3 also has a pump port 23, which is connected to a pump (not shown) that can generate a vacuum in the vacuum chamber 17 of the main body 3. Pump port 13 and pump port 23 can be connected to the same pump, in which case the vacuum in the vacuum chamber 17 can be generated via valves independently of the vacuum generation in the airlock chamber 9. Alternatively, pump port 23 can be connected to a different pump than the one connected to pump port 13, in which case the two pumps can be controlled independently.

[0031] The airlock 5 further comprises a support 25 onto which an object holder 27, carrying an object 29 to be examined, can be placed. The support 25 has a clamp 31 with which the object holder 27 can be temporarily attached to the support 25. The airlock 3 further comprises a seal 33 for sealing the vacuum in the airlock chamber 9. The seal 33 also serves as a movable support for a transfer device 35. The transfer device 35 comprises a rod 37 that passes through the seal 33 and can be slid within the seal 33 along a direction of expansion of the rod 37. The transfer device 35 further comprises a coupling 38, which will be described in detail later, as well as a temperature sensor 39 and a heater 41. The temperature sensor 39 is connected to the control unit 21 via a signal line 43 through a vacuum feedthrough 45.The temperature sensor 39 is capable of measuring the temperature of the rod 37 and, in particular, the coupling 38, and sending a temperature-corresponding signal 38 to the controller 21. The seal 33 can, for example, be designed as a rubber seal.

[0032] The rod 37 of the transfer device 35 can alternatively 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 from the vacuum chamber 17 into the airlock chamber 7, coupled to the object holder 27, and the object holder 27 can be pulled by the transfer device 35 from the airlock chamber 7 into the vacuum chamber 17.

[0033] The heater 41 is connected to the control unit 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 can also be a coolant line through which the control unit 21 supplies the heater 41 with a coolant for cooling or heating the coupling 38 of the rod 37.

[0034] Lock 5 also includes a Fig. 1 loading door (not shown) that can be opened to place the object holder 27 with the object 29 onto the support 25 of the airlock 5. The airlock 5 also includes a position sensor 49 that is at least capable 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 so that an object holder 27 can be placed onto the support 25 in such a way that the object holder 27 can be coupled to the rod 37 in a suitable manner by means of the coupling 38. However, the position sensor 49 can also be configured to detect a transfer position of the rod 37. This can be implemented, for example, by recognizing a pattern attached to the rod 37. The position sensor 49 is connected to the control unit 21 via a signal line 51.Thus, the control unit 21 can also actuate the actuator 16 to open the airlock door 15 if the rod 37 is not fully retracted, and actuate the actuator 16 to close the airlock door 15 if the rod 37 is fully retracted. Furthermore, the control unit 21 can prevent the loading door from opening if the rod 37 is not fully retracted and the airlock door 15 is open, in order to prevent a deterioration of the vacuum in the vacuum chamber 17. For example, the control unit 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 airlock door 15 is closed, and the loading door can be opened.

[0035] The Fig. Figure 1 shows, in dashed lines and with the aid of arrow 53, the process of inserting the object holder 27 and the object 29 attached to the object holder 27 into the vacuum chamber 17 using the transfer device 37. To transfer the object holder 27 into the vacuum chamber 17, the rod 37 is attached to the object holder 27 by means of the coupling 38 and the rod 37 is moved in the direction of arrow 53. This movement is carried out, for example, by a user of the particle beam system 1 pushing the rod 37. Pushing the rod 37 exerts a force on the object holder 27, which releases it from the clamp 31 and moves it along the direction of arrow 53. Then a transfer begins in which the control unit 21 operates the actuator 16 to open the airlock door 15 and the heater 41 to heat the object holder 27, and the object holder 25 is placed on an object table 55, which is arranged inside the vacuum chamber 17, by pressing the rod 37.The transfer begins as soon as the object holder 27 leaves the support 25. The object holder 27 leaving the support 25 means that it is no longer in contact with it. For example, the object holder 27 leaving the support 25 can also be defined by the fact that the distance between one end of the rod 37 inside the airlock 7 or inside the vacuum chamber 17 and an end of the object table 55 facing the support 25 is less than the 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. After the transfer has begun, the object holder 27 is in a transfer position. An example of such a transfer position is one in . Fig. Figure 1 shows intermediate position 18, depicted in dashed lines, in which the rod 37 is pushed so far that the object holder 27 has already passed through the airlock 15 and is located in the vacuum chamber 17. Due to the arrangement of the temperature sensor 39 and the heater 41 on the rod 37, the object holder 27 can still be heated even in intermediate position 18. In particular, when the object holder 27 is in intermediate position 18, only a small amount of the heat supplied by the heater 41 flows through the rod 37, and, more importantly, no excessive amount of the heat supplied by the heater 41 can flow through other components of the particle beam system 1. After the rod 37 has been positioned on the object holder 27, which is shown in the Fig. As shown in Figure 1 by the dashed lines depicting the object holder 27 on the object table 55, the rod 37 can be detached from the object holder 27 and withdrawn. Fig. Figure 1 shows the rod 37 in dashed lines in a state detached from the object holder 27 and partially withdrawn.

[0036] Heating of the object holder 27 by the heater 41 can also be carried out when the object holder 27 rests on the support 25 and is coupled to the rod 37.

[0037] The object stage 55 is enclosed in a positioning system 54. The positioning system 54 further comprises a base 58, which is attached to the vacuum chamber 11, and an actuator 56, which can be operated to displace the object stage 55 relative to the base 58. The object stage 55 also includes a clamp 60, which serves to temporarily secure the object holder 27 to the object stage 55. When the object holder 27 is placed on the object stage 55, it is slid onto the object stage 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. If the rod 37 could not be released from the object holder 27, it would follow the movement of the object holder 27 during positioning of the object 29 by the positioning system 54 and would place excessive stress on the seal 33.In particular, if the signal line 43 and the supply line 47 could not be detached from the object holder 27, the signal line 43 and the supply line 47 would follow the movement of the object holder 27 when the object 29 was positioned, and there would be a possibility that the signal line 43 and the supply line 47 would interfere with functions of the particle beam system 1, for example by tangling, knotting or the like.

[0038] A temperature sensor 57 is attached to the object stage 55, enabling it to measure the temperature of the object stage 55. The temperature sensor 57 is connected to the controller 21 via a signal line 59 through a vacuum feedthrough 61. The controller 21 can thus compare the measured temperature of the object stage 55 with the measured temperature of the coupling 38 of the rod 37, which represents the temperature of the object holder 27 during coupling of the rod 37 with the object holder 27. The controller 21 then supplies sufficient power to the heater 41 via the supply line 47 to heat the coupling 38 and, consequently, the object holder 27 during transfer along arrow 53, thereby saving time that would otherwise be required for heating.

[0039] The following is an image taken with the particle beam system 1 with reference to Fig. 1 described. 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 released upon heating, and an accelerating electrode, which accelerates the particles released from the particle emitter in a predetermined direction.

[0040] The main body 3 further comprises a beam tube 67, which has 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 its upper end 69. The particle beam 65 then passes through a condenser lens 73. The condenser lens 73 comprises a pole piece 75 and a coil 77, which concentrically surround the beam tube 67. When an electric current is applied, the coil 77 generates a magnetic field that enters the beam tube 67 at an opening in the pole piece 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, the magnetic field is deflected in a radial direction with respect to an optical axis of the particle beam system 1, which is Fig. 1 coincides with the particle beam 65. 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.

[0041] The particle beam 65 further passes through an objective lens 79. The objective lens 79 comprises a pole piece 81 and a coil 83, which concentrically surround the beam tube 67. When an electric current is applied, the coil 83 generates a magnetic field that enters the beam tube 67 at an opening in the pole piece 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 tube 67, the magnetic field is deflected in a radial direction with respect to the optical axis of the particle beam system 1. Accordingly, the objective lens 79 has a focusing effect. The focusing effect of the objective lens 79 is generally used to focus the particle beam 65 onto the object 29 under investigation when the object 29 and the specimen holder 27 are arranged on the specimen table 55. Although the condenser lens 73 and the objective lens 79 are in the in Fig. In the case shown, magnetic lenses are used; however, the condenser lens 73 and / or the objective lens 79 can also be implemented by other lenses that can provide a suitable focusing effect for the particle beam 65. For example, single lenses can also be used.

[0042] When the particle beam 65 strikes the object 29, electrons are emitted from it. The beam tube 67 is at a suitable potential relative to the object 29 in order to generate an electric field through the potential difference between the lower end 71 of the beam tube 67 and the object 29. This electric field causes the electrons emitted by the object 29 to be drawn into the beam tube 67 upon impact of the particle beam 65, where they strike a detector 85. The detector then generates a signal based on the electrons striking the detector 85.

[0043] 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 strikes various points on the object 29. The deflection system 87 is implemented, for example, by several coils that 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 on the deflection system 87. The deflection system 87 can also be implemented, for example, by pairs of electrodes between which an electric field can be generated to deflect the particle beam 65.

[0044] If the signals detected by 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 object 29. The generated image can also be displayed to the user of particle beam system 1 on a screen.

[0045] The Fig. Figure 2 shows a top view inside lock chamber 7 of the in Fig. 1. Particle beam system shown 1. The Fig. Figure 2 also shows the loading door 89 of the airlock 5, which can be opened to place the object holder 27 on the support 25. The object holder 27 includes 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, for example, a rotatable relative to the rod 37 is located within the rod 37. Fig. 2. An inner rod (not shown) is provided, which is firmly connected to the thread 93. This configuration allows the thread 93 to be screwed into the threaded hole 91 without causing any additional movement of the signal line 43 and the supply line 47. The temperature sensor 39 and the heater 41 are also attached to the coupling 38. The temperature sensor 39 has a terminal 40 to which the temperature sensor 39 is connected to the signal line 43, which is in Fig. 1 is shown and runs through the lock chamber 7 and the vacuum feedthrough 45 to the control unit 21. The heater 41 is located in the Fig. In the embodiment shown in 2, this is implemented as a heating coil, which is an example of a heating resistor. The heating coil comprises windings that run around the rod 37 at the coupling 38 and have terminals 42 at which the heating coil is connected to the supply lines 47, which in turn, as shown in 2, are connected to the supply lines 47. Fig. 1 shown, connected to the control unit 21 via the vacuum feedthrough 45.

[0046] The in Fig. The position sensor 49 shown in Figure 2 includes a stopper 95 that limits the retraction of the rod 37 through the seal 33. The position sensor 49 further includes a touch switch 50, which is arranged within the seal 33 such that the touch switch 50 can detect contact with the stopper 95. The touch switch 50 is connected to the control unit 21 via the signal line 51 and sends a corresponding signal to the control unit 21 when it detects contact with the stopper 95.

[0047] The following describes another embodiment with reference to the Fig. 3 described. Components that are similar to those described with reference to Fig. 1 and Fig. Embodiments similar in form and function to those described in section 2 are designated with the same reference numerals, further distinguished by the additional letter 'a'. Redundant descriptions are omitted below.

[0048] Fig. Figure 3 shows a cross-section of the lock chamber 7a of the particle beam system 1a according to a further embodiment. Fig. Figure 3 shows that the signal line 43a of the temperature sensor 39a, the supply lines 47a of the heater 41a, and the signal line 51a of the position sensor 49a are routed inside the rod 37a. This has the advantage that the Fig. The vacuum feedthrough 45 shown in Figure 1 in the lock wall 9 does not need to be provided in the present embodiment, which simplifies the manufacture of the lock wall 9a. Furthermore, the signal lines 43a, 51a and the supply lines 47a are not freely located within the lock chamber 7a, where they could easily become entangled, knotted, or similarly obstructed, thus impairing the functions of the particle beam system 1a. For this reason, in the present embodiment, the signal lines 43a, 51a and the supply lines 47a pass through the rod 37a in such a way that they are led out of the lock chamber 7a through the seal 33a. Outside the lock chamber 7a, the signal lines 43a, 51a and the supply lines 47a can leave the staff 37a and be led outside the lock chamber 7a to the control unit 21a.

[0049] The supply lines 47a can also be routed inside the rod 37a from the lock chamber 7a if the heater 41a is a coolant-operated heater. In such a case, the supply lines 47a inside the rod 37a are also coolant lines through which a coolant can be supplied to the heater 41a.

[0050] The Fig. Figure 3 further shows the inner rod 96, which is fixedly connected to the thread 93a and rotatably mounted in the rod 37a. The inner rod 96 protrudes from the rod 37a at one end outside the airlock 5a, allowing a user of the particle beam system 1a to rotate the inner rod 96 relative to the rod 37a in order to screw the thread 93a into the threaded hole 91a. This configuration makes it possible to screw the thread 93a into the threaded hole 91a without rotating the rod 37a, thus preventing excessive twisting and unnecessary stress on the signal line 43a and the supply lines 47a.

[0051] In the following, another embodiment will be described with reference to the Fig. 4 described. Components that are similar to those described with reference to Fig. 1 and Fig. Embodiments similar in form and function to those described in section 2 are designated with the same reference numerals, further distinguished by the additional letter b. Redundant descriptions are omitted below.

[0052] Fig. Figure 4 shows a schematic view of a coupling 38b of a transfer device 35b of a particle beam system 1b. Similar to the one in Fig. 3. The embodiment shown is in Fig. 4. The signal lines 43b and the supply lines 47 are guided through the rod 37b. As in the previous embodiments, an inner rod 96b is arranged inside the rod 37b, which is rotatably mounted relative to the rod 37b and is fixedly connected to the thread 93b. By rotating the inner rod 96b, the thread 93b can be screwed into the threaded hole 91b in the object holder 27.

[0053] The object holder 27b additionally comprises the temperature sensor 39b and the heater 41b. The temperature sensor 39b is connected to terminal sockets 101 via signal lines 99. In the present embodiment, the heater 41b is designed as a heating resistor and is connected to terminal sockets 105 via signal lines 103. The coupling 38b further comprises a head 107. The head 107 is fixedly connected to the rod 37, and the inner rod 96b is rotatably mounted through the head 107 to the thread 93b. Accordingly, the thread 93b can rotate relative to the head 107. The head 107 includes connector plugs 109 which are electrically connected to the signal lines 43b and fit into the connection sockets 101, so that when the rod 37b is coupled to the object holder 27b the connector plugs 109 can be inserted into the connection sockets 101 to establish an electrical connection between the signal lines 99 and the signal lines 43b.The head 107 further includes connector plugs 111 which are electrically connected to the supply lines 47b and fit into the connection sockets 105, so that the connector plugs 111 can be inserted into the connection sockets 105 when coupling the rod 37b to the object holder 27b in order to establish an electrical connection between the signal lines 103 and the supply lines 47b.

[0054] It should be noted that the heater 41b may also include a Peltier element to cool the object holder 27b. Furthermore, it is possible that the heater includes a part that is heated or cooled by a medium, such as a coolant. In such a case, for example, the connecting plugs 111 are designed as a pipe connector so that the medium can flow to the heater after the rod 37b is coupled to the object holder 27b.

[0055] The following describes a procedure for operating the [system / system] with reference to the Fig. The particle beam system is described in sections 1 to 4. Fig. Figure 5 shows a flowchart of a procedure for operating the in Fig. The particle beam system 1 shown in one embodiment. The method comprises steps S1 to S13.

[0056] First, in step S1, the user of particle beam system 1 attaches object 29 to object holder 27. In step S2, the user then retracts the rod 37 of the transfer device 35 until the position sensor 49 signals to the controller 21 that the rod 37 is fully retracted. The controller 21 then operates the actuator 16 via the signal line 19 to close the airlock door 15 and, after the airlock door 15 has closed, informs the user via a display that the loading door 89 can be opened. The user opens the loading door 89 and positions the object holder 27 on the support 25 by sliding the object holder 27 into the clamp 31.

[0057] In step S3, the user of particle beam system 1 advances the rod 37 towards the object holder 27 until the thread 93 engages the threaded hole 91, and then screws the thread 93 into the threaded hole 91. To do this, the user rotates the inner rod 96 about its axis of symmetry. While screwing the thread 93 into the threaded hole 91, the user can keep the loading door 89 at least partially open to visually monitor the progress of the screwing. Once the user has fully screwed the thread 93 into the threaded hole 91, they close the loading door. The controller 21 can then operate the actuator 16 to open the airlock door 15 when the user signals to particle beam system 1 that they have terminated the coupling between the transfer device and the object holder 27. Such signaling by the user can be done, for example, by pressing a button.It should be noted that the controller 21 can operate the heater 41 to heat the object holder 27 as soon as the user signals that step S3 has been completed.

[0058] In step S4, the user begins to push the rod 37 of the transfer device into the particle beam system 1 in the direction of arrow 53. If the controller 21 detects, for example based on a signal from the position sensor 49, that the object holder 27 is already resting on the object table 55, the controller 21 informs the user that step S4 can no longer be performed.

[0059] In step S5, it is checked whether the object holder 27 has left the support 25 of the lock 5. This check can be implemented in various ways. For example, the position sensor 49 can detect a transfer position of the object holder 27 and compare it with a predetermined position of the support 25. Alternatively or additionally, another sensor arrangement can be provided in the support 25 to detect whether the object holder 27 is still resting on the support 25, or the user can signal that the object holder has left the support 25. If the controller 21 determines that the object holder 27 has not yet left the support 25, the rod 37 must be advanced by the user in step S4. If the controller 21 determines in step S5 that the object holder 27 has left the support, the controller 21 proceeds to step S6.It should be noted that in a case where the user of the particle beam system 1 does not need to signal, or does not signal, the end of the coupling of the transfer device 35 with the object holder 27, the airlock door 15 can be opened when the control 21 determines that the object holder 27 has left the support 25.

[0060] In step S6, the temperature sensor 57 measures the temperature of the object stage 55 and transmits the corresponding signal to the controller 21 via the signal line 59. In step S7, the temperature sensor 39 measures the temperature of the object holder 27 and transmits the corresponding signal to the controller 21 via the signal line 43.

[0061] In step S8, the controller compares the measured temperature of the specimen stage 55 and the measured temperature of the specimen holder 27. Specifically, the controller 21 checks whether the measured temperature of the specimen holder 27 is equal to the measured temperature of the specimen stage 55, in order to prevent drift of the specimen holder 27 relative to the specimen stage 55. If the two measured temperatures are not equal, the controller 21 proceeds to step S9.

[0062] In step S9, the controller 21 determines a heating current to be supplied to the heater 41 based on the measured temperatures. The heating current here refers to a current that is to be supplied to the heater. Accordingly, the heating current 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 stage 55. Preferably, the heating current is determined such that the equalization of the temperatures of the object holder 27 and the object stage 55 is expected to be complete when the object holder 27 is slid onto the object stage 55. The heating current determined by the controller 21 is then supplied to the heater in step S10.

[0063] Although in steps S9 and S10 of the Fig.Since section 5 describes the determination and supply of a current, steps S9 and S10 can, for example, also include the determination and supply of a coolant flow rate if the heater 41 can be operated with a coolant. Alternatively or additionally, step S9 can also be used to determine the duration for which the heater 41 must be operated with a given heating current to heat the object holder 27 and reach a target temperature. In such a case, the given heating current is supplied to the heater 41 for the specified duration in step S10.

[0064] After the specified heating current is supplied to the heater 41, steps S4 to S10 are repeated until the controller 21 determines that the temperature of the object holder 27 equals the temperature of the object stage 55. When the controller 21 determines that the temperature of the object holder 27 equals the temperature of the object stage 55, it waits for user input to confirm that the subsequent steps S11 and S12 have been completed.

[0065] If the object holder 27 has not yet reached the object stage 55 at the start of step S11, the user of the particle beam system 1 first advances the rod 37 until the object holder 27 reaches the object stage 55 and is temporarily secured to it by the clamp 60. The user then releases the transfer device 35 from the object holder 27 by unscrewing the threaded rod 93 from the threaded hole 91. To do this, the user rotates the inner rod 96 in the opposite direction around its axis of symmetry. After unscrewing the threaded rod 93 from the threaded hole 91, the user retracts the rod 37.

[0066] In step S12, the object 27 is positioned on the object stage 55 by operating the actuator 56, which causes the object stage 55 to move. Once the user has finished positioning the object, they signal to the particle beam system 1, for example by pressing a button, that step S12 is complete.

[0067] In step S13, the particle beam system 1 is operated to generate a particle-optical image by scanning 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 at different points of impact on object 29 and reads a signal from the detector 85 for each point of impact. From this correlation between point of impact and detector signal, the controller 21 generates a particle-optical image and displays it to the user, for example, using a display. It should be noted that the scanning of object 29 can also be performed by a controller other than the controller 21.

[0068] Steps S1 to S13 of the procedure described above can be modified as appropriate. For example, several steps of the procedure can be omitted if the controller 1 determines, based on a signal from 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 include, for example, step S7, or steps S6 to S10.

[0069] For example, the temperature measurement of the object stage 55, performed in step S6, does not need to be carried out after it has been determined in step S5 that the object holder 27 has left the support 25. The temperature measurement of the object stage 55 can also be performed in step S3 if the object holder 27 is still resting on the support 25 in the airlock 5. In such a case, the temperature measurement of the object stage 55 in step S6 cannot be performed. If, in step S5, it is determined 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 stage 55. Step S6 can then be omitted. The object holder 27 can then be heated to the stored temperature of the object stage 55 in steps S7 to S10.This has the advantage that the object holder 27 can be heated more reliably if it is placed on the stage 55 before it reaches the temperature of the stage 55. In particular, in such a case, the target temperature for the object holder 27 cannot be changed by an input of heat, as is the case if the temperature of the stage 55 is measured and the object holder 27 is heated while it is resting on the stage 55.

Claims

[1] Particle beam system (1, 1a, 1b), comprising: a stage (55) for receiving a holder (27, 27a, 27b) with an object (29) held on it, wherein a first temperature sensor (57) is attached to the stage (55); a particle beam source (63) for generating a particle beam (65) directed at the object (29); a vacuum jacket (11) that defines a vacuum space (17) in which at least the object stage (55) is arranged; a lock (5, 5a) coupled to the vacuum chamber (17) with a lock chamber (7, 7a) which is separated from the vacuum chamber (17) by an openable door (15); and a transfer device (35, 35a, 35b) for transporting the object holder (27, 27a, 27b) from the airlock (5, 5a) to the object table (55); 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) which is attached to one end of the rod (35, 35a, 35b) and which is 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 coupling (38, 38a, 38b); and a supply line (47, 47a, 47b) for a heater (41, 41a, 41b) which leads to the coupling (38, 38a, 38b). [2] 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 from the first temperature sensor (39, 39a, 39b) and a signal read in via the signal line (43, 43a, 43b). [3] Particle beam system (1, 1a) according to claim 1 or 2, wherein the second temperature sensor (39, 39a) is attached to the coupling (38, 38a), and the second temperature sensor (39, 39a) is connected to the signal line (43, 43a). [4] 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 detachable connection with a second electrical connector (101) which is attached to the object holder (27b) and to which the second temperature sensor (39b) is connected, which is also attached to the object holder (27b). [5] Particle beam system (1, 1a) according to any one of claims 1 to 4, wherein the heater (41, 41a) is attached to the coupling (38, 38a), and where the heating system (41, 41a) is connected to the supply line (47, 47a). [6] Particle beam system (1b) according to any one of claims 1 to 4, wherein a first supply line connector (111) is attached to the coupling (38b) which is connected to the supply line (47b); wherein the first supply line connector (111) is configured for detachable connection with a second supply line connector (105) which is attached to the object holder (27b) and to which the heater (41b) is connected, which is also attached to the object holder (27b). [7] Particle beam system (1a, 1b) according to any one of claims 1 to 6, wherein the signal line (43a, 43b) and / or the supply line (47a, 47b) is guided inside the rod (37a, 37b) to the coupling (38a, 38b). [8] Particle beam system (1) according to any 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). [9] Particle beam system (1, 1a, 1b) according to any one of claims 1 to 8, further comprising the object holder (27, 27a, 27b). [10] Particle beam system (1, 1a, 1b) according to claim 9, further comprising a support (25) arranged within the lock (5, 5a, 5b) on which the object holder (27, 27a, 27b) can be placed when it is arranged in the lock (5, 5a, 5b). [11] 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). [12] 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 airlock (5, 5a, 5b) to an object table (55) of the particle beam system (1, 1a, 1b) by actuating the transfer device (35, 35a, 35b); Detaching the transfer device (35, 35a, 35b) from the object holder (27, 27a, 27b); Positioning the object (29) by actuating the object table (55); and Scanning the object (29) with a particle beam (65); the transfer includes: Measuring the temperature of the object stage (55); Moving the object holder (27, 27a, 27b) away from the support (25); Heating or cooling the object holder (27, 27a, 27b) after the object holder (27, 27a, 27b) has left the support (25). [13] Method according to claim 12, wherein the heating or cooling comprises measuring a temperature of the object holder (27, 27a, 27b). [14] Method according to claim 13, wherein the heating or cooling further comprises: Supplying heating or cooling power to the object holder (27, 27a, 27b), and Determining the heating power or cooling power based on the measured temperature of the object holder (27, 27a, 27b). [15] 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). [16] Method according to any one of claims 12 to 15, wherein the heating comprises: Supplying a heating current to a heating resistor, wherein the heating resistor is attached to the object holder (27b) or to a coupling (38, 38a) attached to the transfer device (35, 35a). [17] Method according to any one of claims 12 to 16, wherein the cooling comprises: Supplying a current to a Peltier element, wherein the Peltier element is attached to the object holder (27b) or to a coupling (38, 38a) attached to the transfer device (35, 35a). [18] Method according to any one of claims 12 to 17, wherein the heating comprises: Guiding a medium through the object holder (27b) or through a coupling (38, 38a) attached to the transfer device (35, 35a). [19] Method according to any one of claims 12 to 18, wherein the cooling comprises: Guiding a medium through the object holder (27b) or through a coupling (38, 38a) attached to the transfer device (35, 35a). [20] Method according to any one of claims 12 to 19, further comprising: Closing a door (15) between a vacuum chamber (17) in which the object table (55) is arranged, prior to arranging the object holder (55) on the support (25) in the airlock (5, 5a, 5b); and Opening the door (15) before transferring the object holder (27, 27a, 27b) from the airlock (5, 5a, 5b) to the object table (55). [21] Method according to any one of claims 12 to 20, wherein scanning the object (29) with the particle beam (65) further comprises generating an image of the object (29).

Images