System for processing a sample with a laser beam and an electron beam or an ion beam

Abstract

Processing system (1c) for directing multiple energy beams onto a sample (5c) for processing and / or inspection, the processing system comprising: an ion beam column (41c) for generating an ion beam (43c) directed at a processing location (95c, 9c); a laser system for generating a laser beam (93c) directed at the processing location (95c, 9c); an electron beam column (7c) for generating an electron beam (11c) directed at the processing location (95c, 9c);a protective device (161) comprising a drive and an impact surface (163, 165) coupled to the drive, wherein the protective device (161) is configured to move the impact surface (163, 165) back and forth between a first position and a second position by means of the drive, wherein the impact surface (163, 165) is arranged in the first position in front of a component of the ion beam column (41c) to protect this component from particles that are generated or released when the sample (5c) is processed with the laser beam (93c), and wherein the impact surface (163, 165) is arranged in the second position at a greater distance from the component than in the first position.

Description

Scope of the invention The invention relates to a system for processing a sample with multiple energy beams. The multiple energy beams can, in particular, comprise a laser beam, an electron beam, and an ion beam. Furthermore, the system can be used to examine the sample with one of the energy beams. Brief description of the related state of the art The production of miniaturized components requires the modification of a sample by removing material from it or by depositing material onto it, with the progress of this processing being observed using an electron microscope. Systems are known in which an electron microscope is used to examine the sample, and in which the beam generated by the electron microscope is also used to activate a process gas supplied to the sample, so that the activated process gas modifies the sample. Furthermore, systems are known that comprise an electron microscope and an ion beam column, the beams of which can be simultaneously directed at a location on the sample to be modified. Here, the ion beam serves to modify the sample, and the progress of this process can be observed simultaneously with the electron microscope. In such a system, process gas can also be supplied to further modify the sample through the process gas, which is activated by the electron beam or the ion beam. One problem with such systems is that while processing with the ion beam and activated process gas is possible with very high precision, it is also very slow. If a large amount of material needs to be removed from the sample in a single process, this takes a relatively long time. Systems are known in the art in which a laser beam is used to remove material from a sample. Material removal with a laser beam is often significantly faster than with an ion beam or an activated process gas. However, processing with a laser beam generally exhibits considerably lower precision than processing with an ion beam or an activated process gas. From US 5 055 696 A, a processing system with an electron beam and a laser beam is known, wherein a sample mounted on a sample holder, together with the sample holder, can be transferred back and forth between a processing position with the electron beam and a processing position with the ion beam. US 5 905 266 A discloses a particle beam system comprising a vacuum chamber, an optical microscope with a viewing area on a first region of the vacuum chamber, a laser whose laser beam is directed on the first region, and a particle beam column for generating a beam of charged particles which is directed on a second region in the vacuum chamber, wherein a sample can be transported between the first region and the second region within the vacuum chamber. JP S62 - 071 158 A discloses a combined system comprising a particle beam column for generating a beam of charged particles for capturing an image of a sample and a laser for cutting the sample. US 4 683 378 A relates to a system for generating a focused ion beam with a sample stage whose position is detected using laser technology. JP S58 - 164 135 A relates to a semiconductor processing device for processing a semiconductor product with a focused ion beam. JP S58 - 110 042 A relates to a system with an electron beam column and a laser with a common working area. JP H05 - 314 941 A relates to a system with an electron beam column and an ion beam column with a common working area. US 2007 / 0181828A1 concerns an electron beam lithography device with a vacuum chamber having multiple sections and airlocks between the sections. US 2008 / 0018460A1 discloses a system with a vacuum chamber. One working area in the vacuum chamber is the common working area of ​​several instruments (ion beam column, gas applicator, etc.). Another working area in the vacuum chamber is the common working area of ​​several other instruments (particle beam column, detector). US 6,023,068 A discloses a device for manufacturing semiconductor devices. The device comprises several different exposure systems and multiple working areas within a vacuum chamber. Therefore, there is a need for a system that combines the advantages of the aforementioned sample processing options. Overview of the invention It is an object of the present invention to propose processing systems in which several energy beams can be directed onto a sample for processing and / or inspection. This object is achieved by providing a processing system with the features of claim 1. Advantageous embodiments are specified in the dependent claims. Examples of implementation Exemplary embodiments of the invention are explained below with reference to the figures. Figure 1 shows a schematic front view of a sample holder, which, according to embodiments of the invention, can be used to hold a sample for processing by a particle jet; Figure 2 shows a schematic detail view from the side of the sample holder shown in Figure 1; Figure 3 shows a schematic representation corresponding to Figure 2 according to a further embodiment of a sample holder; Figure 4 shows a schematic side view of a processing system with processing locations arranged at a distance from one another; Figure 5 shows a schematic side view of a processing system with processing locations arranged at a distance from one another; and Figure 6 shows a schematic side view of a processing system according to an embodiment of the invention. The following section explains embodiments of the invention in conjunction with the figures. Components that are identical in structure and function are identified by reference numerals, each with an additional letter for differentiation. Therefore, reference is also made to the entire preceding and subsequent descriptions for further explanation of the components. Fig. 1 is a schematic front view of a part of a processing system 1 and serves to illustrate the functionality of a sample holder 3, which, according to embodiments of the invention, can be used to hold a sample 5 in front of a particle beam column 7. In the embodiment described here, the particle beam column 7 is an electron beam column for generating an electron beam 11 directed at a first processing location 9. The sample holder 3 is configured to position a surface of the sample 5 at the processing location 9 and to move it in both the x-direction and the y-direction, and to pivot it about an axis 13 oriented parallel to the y-direction, which is located near or passes through the processing location 9. The sample 5 is held by a holder 15 of a positioning table 17.Sample 5 can rest against stops on the holder and be sufficiently fixed by adhesion or clamping. The positioning device 17 comprises a base 19, relative to which an intermediate component 21 can be moved back and forth in the y-direction by a drive (not shown in Fig. 1), as indicated by arrow 23. The holder 15 can be moved back and forth relative to the intermediate component 21 in the x-direction by a drive (not shown in Fig. 1), as schematically indicated by arrow 25 in Fig. 2. The base 19 rests on a support 27, which is mounted on a base 29 of the sample holder 3 by a pivot bearing 31 and is pivotable about the axis 13. Additionally, the positioning device 17 can include a further intermediate component to displace the sample 5 relative to the base 29 in the z-direction. The pivotability about the axis 13 is indicated in Fig. 2 by an arrow 24. Fig. 4 is a schematic overview of the machining system 1 with machining locations arranged at a distance from each other, although the base 29 of the sample holder 3 explained with reference to Fig. 1 is not shown. The processing system 1 comprises two particle beam columns, namely the electron beam column 7 for generating the electron beam 11 and an ion beam column 41 for generating an ion beam 43, which, like the electron beam 11, is directed towards the processing location 9. The electron beam column 7 comprises an electron source 45 with a cathode 47, a suppressor electrode 49', an extractor electrode 49" and an anode electrode 49'", a condenser lens system 51 for generating the beam 11, a secondary electron detector 53 arranged, for example, within the column 7, and an objective lens 54 to focus the electron beam 11 at the processing location 9. Beam deflectors 55 are provided to vary the point of impact of the electron beam 11 on the sample 5 and, for example, to scan an area of ​​the sample surface and detect the particles generated or released in the process, in this embodiment secondary electrons, with the detector 53 in order to obtain an electron microscopic image of the sample 5 in the scanned area at the processing location 9.In addition to the detector 53 arranged within the column 7, one or more secondary particle detectors, such as an electron detector 57 or an ion detector, can be provided next to the column 7 within a vacuum chamber 59 near the processing location 9, for example, to also detect secondary particles. The ion beam column 41 comprises an ion source 61 and electrodes 63 for shaping and accelerating the ion beam 43, as well as beam deflectors 65 and focusing coils or focusing electrodes 67, in order to also focus the ion beam 43 at the processing location 9 and to scan an area of ​​the sample 5 there. A gas supply system 69 comprises a reservoir 71 for a process gas, which can be supplied to the sample 5 via a line 73 that terminates near the processing location, controlled, for example, by a valve 75. The process gas can be activated by the ion beam or the electron beam to remove material from the sample 5 or to deposit material there. The progress of this processing can be observed by the electron microscope 7. Material removal can also be achieved solely by processing with the ion beam and without the supply of process gas. The vacuum chamber 59 is bounded by a vacuum jacket 79, which has a pump nozzle 81 connected to a vacuum pump and which can be vented via a nozzle 83. In order to keep the electron source 45 permanently under a sufficiently good vacuum, even when process gas is introduced into the vacuum chamber 59, the electron column 7 includes a pressure orifice 84 and a further pump nozzle 85 to pump out the area of ​​the electron source 45 by means of a separate vacuum pump. Background information on systems which use multiple particle beams to process a sample can be obtained, for example, from US 2005 / 0 184 251 A1, US 6 855 938 B2 and DE 10 2006 059 162 A1, the disclosure of which is fully incorporated into the present application. The processing system 1 further comprises a laser system 91, which is configured to direct a laser beam 93 to a second processing location 95. For this purpose, the laser system 91 includes a laser 97 and collimation optics 99 to shape the laser beam 93. The laser beam 93 is guided via one or more mirrors 101 or optical fibers to a location near the vacuum chamber 79 and there strikes a swivel mirror 103, which directs the beam towards the second processing location 95 and is swivelable, as indicated by an arrow 105, so that the beam 93 can scan an area on a sample located at the second processing location 95. Here, the laser beam 93 enters a vacuum chamber 109 through a window 107. This vacuum chamber is also bounded by the chamber wall 79, but can be separated from the vacuum chamber 59 by an openable door 111. Fig. 4 shows a locking plate 113 of the door 111: solid line in the open state and dashed line in the closed state. An actuator rod 114 of the door serves to move the locking plate 113 to move the door from its open to its closed state. The door 111 can be designed as a vacuum seal by being sealed against the chamber wall 79 to maintain different vacuum pressures in the vacuum chambers 59 and 109. The vacuum chamber 109 is evacuated via a pump nozzle connected to a vacuum pump and can be vented via another nozzle 116. Sample 5 can be transported back and forth between processing location 9 and processing location 95 by a transport device 121. For this purpose, the transport device 121 comprises a rod 123 which enters the vacuum chamber 109 through a vacuum feedthrough 125. The vacuum feedthrough 125 is thus located closer to processing location 95 than to processing location 9. A coupling 127 is provided at one end of the rod 123, which is connected to the base 19 of the positioning table 17. In Fig. 4, the positioning table 17 is in a position such that the sample 5 is arranged at the processing location 9 for inspection or processing with the electron beam 11 or the ion beam 43. In the dashed line representation, the positioning table 17 in Fig. 4 is shown in a position such that the sample 5 is arranged at the processing location 95 for processing by the laser beam 93. The transport device 21 allows the positioning table 17, together with the sample 5, to be moved back and forth between these two positions. For this purpose, the transport device 121 includes a rail 131 to support the positioning table 17 against gravity during transport and during its positioning at the processing location 95. When the table is in its position at the processing location 9, it is supported by the carrier 27 of the sample holder 3, as described above. In Fig. 4, a gap 133 is provided between the support 27 and the rail 131 to allow the support 27 to pivot about the axis 13 without colliding with the rail 131 after the linkage 123 has been released from the coupling 127 and retracted slightly (to the left in Fig. 4). However, it is possible to pull the base 19 of the positioning device 17 across this gap onto the rail 131. The rail 131 also has a gap 135 that passes through the plate 113 when the door 111 is in its closed position. The door 111 can then be closed when the transport device 123 has pulled the positioning device 17 into the position at the machining location 95, or when only the linkage 123 in Fig. 4 has been fully retracted to the left, with the positioning device remaining in the position at the machining location. At location 95, sample 5 is processed with laser beam 93, whereby particles evaporating from or detaching from sample 5 degrade the vacuum in vacuum chamber 109. The closed door 111 then prevents a deterioration of the vacuum in vacuum chamber 59 or sustained contamination of vacuum chamber 59, thereby protecting, among other things, particle beam columns 7 and 41. The processing of sample 5 by the laser beam 93 is monitored by an endpoint detection device 141, which includes, for example, a light source 143 for generating a light beam 144 and a light detector 145. The light beam 144 enters the vacuum chamber 109 through a window 146 and is directed towards the processing location 95. The light detector 145 receives light 147 emanating from the processing location 95 through a window 148. By analyzing the light received by the detector 145, it is possible to determine the processing status of sample 5 by the laser beam 93 and, in particular, to terminate this processing.After completion of this processing by the laser beam, the door 111 is opened and the transport device 121 transports the sample 5 together with the positioning table to the processing location 9, where further processing of the sample 5 is carried out with the ion beam 43 and supplied process gas, which is observed by the electron microscope 7. The positioning of the positioning table 17 onto the carrier 27 can be carried out with high precision. Fig. 2 shows a stop 22 against which the base 19 of the positioning table 17 can be pressed by the transport device 121 before the coupling 127 is released. Fig. 3 presents an alternative embodiment. Fig. 3 shows a positioning table 17a in a representation corresponding to Fig. 2, wherein the position of a base 19a of the positioning table 17a relative to a support 27a of a sample holder 3a is determined by an optical measuring system 151. The optical measuring system 151 emits a light beam 152, which is reflected by a mirror 153 attached to the base 19a, so that the measuring system 151 can determine a distance to the base 19a. By actuating the linkage 123, it is thus possible to move the positioning table 17a into a predetermined position on the support 27a in front of the particle jet columns. Fig. 5 schematically shows an alternative overview of a processing system 1b with processing locations arranged at a distance from one another. In contrast to the processing system described with reference to Fig. 4, processing system 1b has a transport device 121b for transporting a sample 5b back and forth between a processing location 9b for processing by particle beams 11b and 43b and a processing location 95b for processing by a laser beam 93b. This transport device includes a linkage 123b, at one end of which a gripper 127b is attached, which can detachably grasp the sample 5b. Thus, in the embodiment shown in Fig. 5, the sample 5b is transported back and forth between the two processing locations 9b and 95b without moving a positioning table 17b. The positioning table 17b remains at the processing location 9b during transport. At processing location 95b, the sample 5b is placed by the gripper 127b onto a separate positioning table 18b. The positioning table 18b can have a simpler design than the positioning table 17b. In particular, the positioning table 18b does not need to allow the sample to be pivoted about an axis, and it can also be translationally displaceable about fewer axes, since the laser beam 93b can be scanned by a swiveling mirror 103b over an area of ​​the surface of the sample 5b that is larger than the area over which the electron beam 11b or the ion beam 43b can be scanned. In this case, positioning of the sample in the z-direction can also be omitted if, for example, the collimation optics 99b can be displaced in the z-direction. Fig. 6 is a schematic representation of an embodiment of a processing system 1c according to the invention, which has a similar structure to the processing systems described with reference to Figs. 4 and 5. In contrast to these previously described processing systems, however, the processing system 1c is configured such that a processing location 9c for processing by a particle beam, such as an electron beam 11c and an ion beam 43c, and a processing location 95c for processing by a laser beam 93c essentially coincide. The processing locations 9c and 95c are arranged in a common vacuum chamber 59c. Therefore, the processing system 1c does not include a transport device for transporting the sample between the two processing locations. However, the processing system 1c includes a protective device 161, which comprises a cup-shaped impact surface 163, as shown in Fig.The protective device 161 partially encompasses components of an electron beam column 7c in the position shown in Figure 6. Furthermore, the protective device 161 includes a cup-shaped impact surface 165, which partially encompasses components of an ion beam column 41c. The impact surfaces 163 and 165 arranged in this position protect the components of the electron beam column 7c and the ion beam column 41c during the processing of a sample 5c by a laser beam 93c. After completion of the processing by the laser beam 93c, the impact surfaces 163 and 165, which are attached to a rod 167, can be retracted into a position in which they do not interfere with the processing by the electron beam 11c and the ion beam 43c. In this position, the rod 167 penetrates a vacuum wall 79b of a vacuum chamber 59b through a vacuum feedthrough 169.The linkage can be moved by a motor drive or by hand to move the impact surfaces 163 and 165 into the retracted position. It may also be possible to cover one or more particle detectors located in the vacuum space with the protective device. In the embodiment described above, the laser system is configured such that the laser beam is directed into the vacuum chamber through a window, and a grid device for the laser beam is located outside the vacuum chamber. According to further embodiments, such a grid device, for example a grid mirror, is also located inside the vacuum chamber, with the light again being introduced into the vacuum chamber through a window. Alternatively, the laser beam can also be guided into the vacuum chamber by another means, such as an optical fiber. The collimation optics can also be located either inside or outside the vacuum chamber. In the embodiment described above, an end-point detection device for laser processing comprises a light source and a corresponding detector. According to further embodiments, it is also possible to detect the end of the processing by the laser beam in a different way. For example, without a separate light source, radiation from the laser beam can be detected by a detector, and the end of the laser processing can be determined from the signal detected. Furthermore, it is possible to detect the laser-induced plasma generated by the laser beam or to selectively generate a plasma using a separate plasma source in which charge carrier recombinations occur that are characteristic of the type of material being processed and can be detected. Alternative embodiments of the disclosed invention are further described by the following aspects: Aspect 1 describes a processing station for directing several energy beams onto a sample for processing and / or inspection, wherein the processing station comprises an electron beam column for generating an electron beam directed at the first processing location and / or an ion beam column for generating an ion beam directed at the first processing location, a laser system for generating a laser beam directed at a second processing location arranged at a distance from the first processing location, a positioning table with a base and a holder for holding a sample in a sample position, wherein the holder is mounted on the base so as to be displaceable relative to it along at least three axes, and a first positioning device configured toThe positioning station comprises a positioning device configured to position the positioning table in a predetermined first position relative to the electron beam column or the ion beam column such that the sample position is located in a region of the first processing location, a second positioning device configured to position the positioning table in a predetermined second position relative to the laser system such that the sample position is located in a region of the second processing location, and a transport device configured to transport the positioning table back and forth between the predetermined first position and the predetermined second position. Aspect 2 describes the processing station according to Aspect 1, wherein the first and / or the second positioning device includes at least one position sensor to detect a position of the positioning table. Aspect 3 describes the processing station according to Aspect 1 or 2.further comprising at least one vacuum container, wherein the first processing location, the second processing location, and a transport path for transporting the positioning table between the first position and the second position are arranged within the at least one vacuum container. Aspect 4 describes the processing station according to Aspect 3, wherein the at least one vacuum container has an openable door to separate a first vacuum space containing the first processing location from a second vacuum space containing the second processing location. Aspect 5 describes a processing station for directing several energy beams onto a sample for processing and / or inspection, wherein the processing station comprises an electron beam column for generating an electron beam directed onto the first processing location and / or an ion beam column for generating an ion beam directed onto the first processing location.A laser system for generating a laser beam directed at a second processing location arranged at a distance from the first processing location, a first positioning table for holding a sample at the first processing location, a second positioning table for holding the sample at the second processing location, and a transport device configured to transport the sample back and forth between the first positioning table and the second positioning table. Aspect 6 describes the processing station according to Aspect 5, further comprising at least one vacuum container, wherein the first processing location, the second processing location, and a transport path for transporting the sample between the first positioning table and the second positioning table are arranged within the at least one vacuum container. Aspect 7 describes the processing station according to Aspect 6, wherein the at least one vacuum container has an openable door.to separate a first vacuum chamber containing the first processing location from a second vacuum chamber containing the second processing location. Aspect 8 describes the processing station according to aspect 7, wherein the transport device has a rod and a gripper attached to one end of the rod for fixing the sample, wherein in a situation where the gripper is located near the first processing location, the rod passes through the open door.

Claims

Processing system (1c) for directing multiple energy beams onto a sample (5c) for processing and / or inspection, the processing system comprising: an ion beam column (41c) for generating an ion beam (43c) directed at a processing location (95c, 9c); a laser system for generating a laser beam (93c) directed at the processing location (95c, 9c); an electron beam column (7c) for generating an electron beam (11c) directed at the processing location (95c, 9c);a protective device (161) comprising a drive and an impact surface (163, 165) coupled to the drive, wherein the protective device (161) is configured to move the impact surface (163, 165) back and forth between a first position and a second position by means of the drive, wherein the impact surface (163, 165) is arranged in the first position in front of a component of the ion beam column (41c) to protect this component from particles that are generated or released when the sample (5c) is processed with the laser beam (93c), and wherein the impact surface (163, 165) is arranged in the second position at a greater distance from the component than in the first position. Processing system (1c) according to claim 1, wherein the impact surface (163, 165) in the first position is further arranged in front of a component of the electron beam column (7c) to protect this component from particles that are generated or released when processing the sample (5c) with the laser beam (93c). Processing system (1c) according to claim 2, wherein the impact surface (163, 165) has a cup shape which in the first position partially surrounds the component of the electron beam column (7c). Processing system (1c) according to one of claims 1 to 3, wherein the impact surface (163, 165) in the first position is further arranged in front of a component of a detector of the processing system to protect this component from particles that are generated or released when the sample (5c) is processed with the laser beam (93c). Processing system (1c) according to one of claims 1 to 4, wherein the impact surface (163, 165) has a cup shape which in the first position partially surrounds the component of the ion beam column (7c). Machining system (1c) according to one of claims 1 to 5, wherein the displacement of the impact surface (163, 165) comprises a translation. Processing system (1c) according to one of claims 1 to 6, wherein the protective device (161) has a pump and a suction hose coupled to the impact surface (163, 165) to at least partially extract the particles. Processing system (1c) according to one of claims 1 to 7, wherein the protective device (161) further comprises a cooled condensation surface, a surface to which a high voltage is applied and / or a plasma source. Processing system (1c) according to one of claims 1 to 8, further comprising a secondary electron detector. Processing system (1c) according to one of claims 1 to 9, further comprising a gas supply system (69) with a reservoir (71) for storing a process gas and a line (73) coupled to the reservoir to supply process gas to the processing location (95c, 9c).

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