Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
  • H01J37/147—Arrangements for directing or deflecting the discharge along a desired path
  • H01J37/1472—Deflecting along given lines
  • H01J37/1474—Scanning means
  • H01J37/1475—Scanning means magnetic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
  • H01J37/09—Diaphragms; Shields associated with electron or ion-optical arrangements; Compensation of disturbing fields
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
  • H01J37/10—Lenses
  • H01J37/14—Lenses magnetic
  • H01J37/141—Electromagnetic lenses
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
  • H01J37/147—Arrangements for directing or deflecting the discharge along a desired path
  • H01J37/1472—Deflecting along given lines
  • H01J37/1474—Scanning means
  • H01J37/1477—Scanning means electrostatic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
  • H01J37/153—Electron-optical or ion-optical arrangements for the correction of image defects, e.g. stigmators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
  • H01J37/28—Electron or ion microscopes; Electron or ion diffraction tubes with scanning beams
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/04—Means for controlling the discharge
  • H01J2237/045—Diaphragms
  • H01J2237/0451—Diaphragms with fixed aperture
  • H01J2237/0453—Diaphragms with fixed aperture multiple apertures
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/153—Correcting image defects, e.g. stigmators
  • H01J2237/1532—Astigmatism
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/245—Detection characterised by the variable being measured
  • H01J2237/24564—Measurements of electric or magnetic variables, e.g. voltage, current, frequency

Definitions

• Multi-beam particle beam system and method for operating such a system
• the invention relates to multi-beam particle beam systems which work with a large number of particle beams, and to methods for operating multi-beam particle beam systems.
• US 2015/0348738 A1 discloses multi-beam particle beam systems which use a plurality of multi-aperture plates in order to divide a particle beam into a multiplicity of particle beams and in order to influence individual particle beams of the multiplicity of particle beams by providing electrical fields.
• ring electrodes are used at openings of a multi-aperture plate through which particle beams pass, in order to provide electrostatic fields focusing the particle beam, and electrodes arranged in the circumferential direction around the openings are used, dipole fields or
• Multi-aperture plates are complex components, the production of which is very complex. Errors that occur inevitably during production lead to one or more electrodes being defective, so that their voltage cannot be set to the desired values during operation. If only one electrode out of the many electrodes of a multi-aperture plate is defective, this usually means that the entire multi-aperture plate is defective and cannot be used. Defects on individual electrodes of a multi-aperture plate that occur during operation also mean that the entire multi-aperture plate must be replaced. A reject perceived as too high in the production of multi-aperture plates and a failure probability perceived as too high during the operation of
• Multi-aperture plates seem to be accepted here. One possible way out of this situation is to develop more reliable ones
• a method for operating a multi-beam particle beam system includes generating a plurality of
• Particle beams pass through a multipole element, each multipole element having a plurality of deflection elements which are arranged circumferentially around a center of the multipole element, and each of the multipole elements is either intact or defective.
• the large number of particle beams can be generated in a variety of ways.
• a particle emitter can be generated with the aid of a particle emitter, which is directed onto a multi-aperture plate with a multiplicity of openings, so that the multiplicity of particle beams is generated in the beam path behind the multi-aperture plate.
• a variety of particle emitters be provided, wherein each particle emitter generates a particle beam of the plurality of particle beams.
• the particle beam system typically comprises particle optics, which directs the large number of particle beams onto an object and focuses there.
• Particle optics do not have to be error-free and can be subject to aberrations.
• one of the aberrations is an astigmatism, the effect of which on a given particle beam of the plurality of particle beams which form a beam, from the position of the particle beam within the
• the multipole elements are provided, each of the multipole elements being penetrated by one of the particle beams.
• Deflection elements of the multipole element which are arranged circumferentially distributed around a center of the multipole element, are excited during operation in order to generate fields which penetrate the multipole element
• the fields influencing the particle beam can be electrical fields and / or magnetic fields.
• the deflection elements can have electrodes for generating electrical fields and coils for generating
• the deflection elements can then be excited such that focusing each of the particle beams in a predetermined plane satisfies at least one predetermined criterion.
• the predetermined plane can be, for example, the surface of an object to which the particle beams are directed.
• the predetermined criterion can, for example, require that the respective particle beam be focused in the predetermined plane in such a way that the cross section of the particle beam in this plane is as small as possible or has a predetermined value, or that the shape of the cross section is one Deviation from a circular shape that is smaller than a limit. Other criteria are possible.
• Another exemplary multipole element has eight in
• a controller In order to excite the deflection elements during the operation of the particle beam system, a controller can be provided, which controls the deflection elements with the
• Deflection elements are electrodes, the electrical lines are electrically conductive connections which are suitable for conducting a voltage provided by the control to the respective electrode. If the baffles are coils, they are Lines of electrically conductive connections which are able to conduct a current necessary to excite the coil to the coil.
• Errors can occur in multi-aperture plates, which lead to individual multi-pin elements not being intact but defective.
• a single deflection element of the multipole element can be defective in that it cannot be excited as desired during operation.
• an electrical line leading to the relevant deflection element can be a
• an electrode which forms the relevant deflection element may have an insulation defect, so that this electrode is conductively connected to the multi-aperture plate or to another electrode and, for this reason, cannot assume a desired voltage.
• a coil, which forms a given deflection element can have an open circuit or a short circuit, so that a
• the method may further include energizing the deflection elements of the multipole elements that are intact with the determined excitations.
• embodiments determine a size for each of the multipole elements, which represents a desired influence on the particle beam passing through the multipole element.
• the at least one size can include, for example, the size of a beam astigmatism, which of the
• Particle beam is such that the influencing of the particle beam represented by the at least one size is achieved.
• the excitations of the deflection elements of each multipole element can in particular be determined in such a way that an average of the excitations of the multipole element has a value that is the same for all multipole elements.
• Average value can be calculated as the arithmetic mean of the excitations of the deflection elements of the multipole element. For example, if the deflection elements are electrodes, determining the excitations includes determining electrical voltages, and energizing the deflection elements includes applying the determined voltages to the electrodes. The mean value of the excitations is then given by the mean value of the voltages applied to the electrodes. If this mean value is the same for all multipole elements operated, for example, as stigmators, the effects of the individual multipole elements or stigmators differ only in terms of their deflecting and
• the deflection elements of the multipole elements which are intact, can then be excited with the excitations determined as described above.
• the method may further include modifying the particular excitations for the deflection elements of at least one multipole element of the multipole elements that are defective and energizing the electrodes of the defective multipole element with the modified excitations.
• the modification of the excitations of the deflecting elements of the defective multipole element takes into account the fact that, for example, the excitation of one of the deflecting elements is not freely adjustable but is fixed.
• modifying the particular excitations includes determining the modulated excitations such that the defective deflecting element is energized such that its excitation is equal to the defined excitation. For example, a correction excitation can be determined, which is added to the determined excitation of the defective deflection element by the to calculate modified excitation, the correction excitation being as large as the difference between the specified excitation and the specific excitation.
• modifying the particular excitations for the deflection elements of a multipole element includes adding correction excitations to the particular excitations.
• the correction excitations are the same for all deflection elements of a given defective multipole element, but they can be different for different defective multipole elements.
• Production of the multi-aperture plates can thus be reduced. If a defect occurs during the operation of the multi-beam particle beam system, the excitation of the deflection elements of the multi-pole elements of the multi-aperture plate can also occur
• Multipole element the previously described modified excitations are supplied. It is thus possible for multi-beam particle beam systems to also exist after defects in multipole elements of a multi-aperture plate
• the at least one deflecting element can comprise, for example, an electrode which is connected to a voltage source in order to supply the electrode with an adjustable voltage in order to generate an electric field or to change an existing electric field which affects the particles of the opening
• Particle beam passes exactly one opening of the plurality of multi-aperture plates, at which the at least one controllable deflection element is provided.
• Multi aperture plates is the number of openings that can be controlled
• Deflection elements have less than the number of particle beams.
• the several multi-aperture plates have in common on the multitude of
• a second subset of openings is provided in at least one of the multiple multi-aperture plates, which are not included in the first subset and which have at least one deflection element, although excitation of this at least one deflection element is fixed and cannot be set independently.
• the openings of the first and the second subset differ in that the deflection elements of the openings of the second subset are not excitable, for example by no supply lines being provided to supply excitation to the deflection elements of the openings of the second subset.
• a method for operating a multi-beam particle beam system comprises a
• Multi-aperture plate with openings, at least one at each
• Electrode is provided as a deflecting element, determining at least one
• Multi-aperture plates for multi-beam particle beam systems are
• a multi-aperture plate comprises a substrate made of doped silicon, which is a conductive material.
• a layer of Si0 2 is applied to the substrate, which acts as an insulator.
• the conductor tracks are formed by an aluminum layer, which was applied to the Si0 2 layer and structured by means of lithographic processes.
• the conductor tracks serve, for example, to supply electrical potentials or electrical currents to the deflection elements which are provided at openings in the multi-aperture plate.
• the conductor tracks should not be interrupted and on the other hand the
• Conductor tracks have no contact with the electrically conductive substrate.
• the insulating Si0 2 layer is too thin and therefore has a finite resistance. A resulting current flow between the conductor track and the substrate can be so great that a voltage or current source for providing the excitations to be supplied to the deflection elements is overloaded. It may be the case that the insulating Si0 2 layer is not uniformly thin, but is too thin in some localized areas due to the manufacturing process. It is assumed that the behavior of the electrical resistance between the conductor track and the substrate has the characteristic of a Schottky contact in these regions.
• High-voltage pulses to a defective interconnect can correct a short circuit between the interconnect and the substrate.
• Multi-aperture plate each at least one controllable deflection element is provided, and a voltage supply system which is configured to supply adjustable excitations via feed lines to the deflection elements of the at least one multi-aperture plate. This means that during the operation of the multi-beam particle beam system, each deflection element of the at least one multi-aperture plate has an adjustable excitation from it
• Power supply system can be supplied.
• Multi-aperture plates can be assigned to several groups of openings, with each opening contained in one group of openings not being contained in another of the groups of openings. This means that several of the groups under consideration do not contain common openings or that the groups are disjoint.
• This possible division of the openings into groups applies to a majority of the openings of the multi-aperture plate, but not necessarily to all openings of the multi-aperture plate. For example, the division into groups applies to more than half of the openings of the multi-aperture plate.
• all openings of each given group of openings each have at least one deflection element which is connected to a given supply line, so that deflection elements from several openings of the same group are connected together to this given supply line.
• Deflection elements of all openings of a multi-aperture plate can be supplied with independently adjustable excitations. This ensures that each particle beam that passes through an opening of the multi-aperture plate can be influenced by the electrical and / or magnetic fields provided by the deflection elements in exactly the same way as is desired or necessary for this particle beam.
• the inventors have found that in practice many deflection elements have to be supplied with the same or similar excitations in order to influence the particle beams with a view to compensating for aberrations of other optical elements in the beam path of the particle beams.
• the inventors have found that if the openings have a plurality of deflecting elements, for example the opening
• neighboring openings receive the same or similar excitation patterns around which the neighboring ones
• the deflection elements which are connected to the common feed line are supplied with the same excitation, so that the excitations of these deflection elements can no longer be set independently of one another.
• Multi aperture plate can be significantly reduced. Nevertheless, it is possible that
• the groups of openings can be chosen so that at least some Deflection elements of the openings of the same group can be supplied with the same excitations.
• a plurality of openings of each given group each have an opening as the nearest neighbor, which also belongs to this given group of openings. This means that in the plane of the multi-aperture plate, closely adjacent openings belong to a common group. The idea behind this is that the neighboring ones
• Openings of the multi-aperture plate require similar excitations for your deflection elements in order to allow the particle beams passing through this opening, for example with a view to compensating for an imaging error of one of the
• Embodiments is a number of openings that belong to the same group of openings, arithmetically averaged over all groups of openings of the multi-aperture plate from a range between 2.0 and 3.0.
• the openings of each given group and in particular the openings of all groups of openings have an equal number of deflecting elements, such as eight deflecting elements, which are arranged circumferentially around the opening.
• Figure 1 is a schematic representation of a multi-beam particle beam system
• Figure 2 is a schematic cross-sectional view of an arrangement
• FIG. 3 shows a top view of a first multi-aperture plate of the illustration in FIG. 2;
• FIG. 4 shows a plan view of a second multi-aperture plate from FIG. 2;
• Figure 5 is a schematic plan view of a variant of the multi-aperture plates of Figures 3 and 4;
• FIG. 6 shows a schematic illustration of an intact multipole element which is excited with certain excitations
• FIG. 8 shows a schematic illustration of the defective multipole element of FIG. 7, which is excited with modified excitations
• FIG. 9 shows a flow chart to explain a method for operating a
• FIG. 10 shows a schematic illustration of beam astigmatisms to be corrected for a multiplicity of openings of a multi-aperture plate
• FIG. 11 illustrates an electrical circuit for feeding
• Figure 12 is a schematic representation of a corresponding to Figure 10
• FIG. 1 is a schematic illustration of a multi-beam particle beam system 1 which works with a large number of particle beams.
• the multi-beam particle beam system 1 generates a multiplicity of particle beams which impinge on an object to be examined in order to generate electrons there which emanate from the object and are subsequently detected.
• the multi-beam particle beam system 1 is of the scanning electron microscope (SEM) type, which uses a plurality of primary electron beams 3 which impinge on a surface of the object 7 at locations 5 and several there
• the object 7 to be examined can be of any type and can comprise, for example, a semiconductor wafer, a biological sample and an arrangement of miniaturized elements or the like.
• the surface of the object 7 is one in an object plane 101
• Objective lens 102 of an objective lens system 100 is arranged.
• the enlarged section II of FIG. 1 shows a plan view of the object plane 101 with a regular rectangular field 103 of impact points 5, which are formed in the plane 101.
• the number of impact locations is 25, which form a 5 ⁇ 5 field 103.
• the number 25 of impact locations is a small number chosen for the sake of simplicity. In practice, the number of rays or impact points can be chosen to be substantially larger, such as 20 x 30, 100 x 100 and the like.
• the field 103 of impact sites 5 is a substantially regular rectangular field with a constant distance PI between adjacent impact sites.
• Exemplary values of the distance PI are 1 micron, 10 microns and 40 microns.
• the field 103 has other symmetries, such as a hexagonal symmetry.
• a diameter of the beam spots formed in the object plane 101 can be small. Exemplary values of this diameter are 1 nanometer, 5 nanometer, 100 nanometer and 200 nanometer.
• the particle beams 3 are focused by the objective lens system 100 to form the beam spots 5.
• the particles hitting the object generate electrons, which are emitted by the
• the inspection system 1 provides an electron beam path 11 in order to supply the plurality of electron beams 9 to a detection system 200.
• the detection system 200 comprises electron optics with a projection lens 205 in order to direct the electron beams 9 onto an electron multi-detector 209.
• the primary electron beams 3 are generated in a beam generating device 300, which has at least one electron source 301, at least one
• Electron beam 309 which is collimated by collimation lens 303 to form a beam 311 which illuminates multi-aperture plate assembly 305.
• the section 13 in Figure 1 shows a plan view of the
• the multi-aperture plate arrangement 305 comprises a multi-aperture plate 313, which has a plurality of ones formed therein
• Center points 317 of the openings 315 are arranged in a field 319 which corresponds to the field 103 which is formed by the beam spots 5 in the object plane 101.
• Openings 315 from one another can have exemplary values of 5 micrometers
• Electrons of the illuminating beam 311 pass through the openings 315 and form electron beams 3. Electrons of the illuminating beam 311, which strike the plate 313, are intercepted by the latter and do not contribute to the formation of the electron beams 3.
• the diameter of the focus 323 can be, for example, 10 nanometers, 100 nanometers and 1 micrometer.
• the field lens 307 and the objective lens 102 provide a first imaging
• Particle optics ready to image the plane 325, in which the foci are formed, on the object plane 101, so that there a field 103 of impact points 5 or beam spots is formed on the surface of the object 7.
• Multi aperture plate 313 are oriented.
• the stigmators 333 of the first multi-aperture plate 331 and the stigmators 337 of the second multi-aperture plate 335 are each formed by eight deflection elements 334, which are arranged circumferentially around the openings 339.
• deflection elements 334 are not provided at each of the openings 339 of the multi-aperture plates 331 and 335. Rather, deflection elements 334 are provided on a first subset of the openings 339 of the first multi-aperture plate 331 and on a first subset of the openings 339 of the second multi-aperture plate 335.
• each particle beam which penetrates openings 339 of the first multi-aperture plate 331 and the second multi-aperture plate 335 passes through exactly one opening 339 on the deflection elements 334 are provided.
• FIG. 3 shows a top view of the first multi-aperture plate 331 with the stigmators 333
• FIG. 4 shows a top view of the second multi-aperture plate 335 with the stigmators 337. It can be seen from FIGS. 3 and 4 that the first and second multi-aperture plates 331, 335 each 61 have openings 339, which are arranged in a hexagonal pattern. Both multi-aperture plates 331 and 335 have openings 339, at which in the circumferential direction around the respective one
• Deflection elements 334 arranged in an opening 339 are provided. However, both multi-aperture plates 331 and 335 also have openings 339 at which no deflection elements 334 are arranged.
• a line 345 in FIG. 3 frames the subset of openings 339 of the first multi-aperture plate 331, which are provided with deflection elements 334. This first subset of
• Openings 339 are 19 openings 339 of the first multi-aperture plate 331, which are arranged centrally in the hexagonal pattern of the openings 339.
• a line 347 in FIG. 3 frames all openings 339 of the first multi-aperture plate 331.
• the openings 339 which are arranged outside the line 345 and inside the line 347, form a second subset of openings 339, at which no deflection elements 334 are provided.
• the openings 339 of the second subset of openings 339 of the first multi-aperture plate 331 lie on the edge of the hexagonal arrangement of openings 339.
• Lines 345 and 347 are also shown in Figure 4. However, there the openings 339, which belong to the first subset of openings 339, on which deflection elements 334 are provided, are arranged outside the line 345 and inside the line 347, while the openings 339 of the second
• Subset with openings 339 which have no deflection elements 334, are arranged within the line 345. It can be seen that the arrangement of the first and second subset of openings 339 on the first
• Multi-aperture plate 331 complementary to the arrangement of the first and second Part of the second multi-aperture plate 335 is such that the condition is met that each particle beam passes through exactly one opening of the two multi-aperture plates 331 and 335, on which deflection elements 334 are provided.
• Each of the two multi-aperture plates 331 and 335 comprises feed lines 349 in order to feed the deflection elements 334 adjustable excitations, which are provided by supply circuits 351. Few of the
• Feed lines 349 are shown in FIGS. 3 and 4. If the
• Deflection elements 334 are electrodes for generating electrical fields, so the supply circuits 351 are voltage supplies. If the deflection elements 334 are coils for generating magnetic fields, then they are
• Supply circuits 351 power supplies.
• the supply circuits 351 are controlled by a controller 353 in order to supply the excitation elements 334 with suitable excitations. It can be seen that the number of supply lines 349 required to excite the deflection elements 334 is a multiple of the number of openings 339 of the first subset. However, since the number of openings 339 of the first subsets of the respective multi-aperture plates 331 and 335 is less than the total number of openings 339 of the respective multi-aperture plate 331 and 335, the number of supply lines 349 is that which is on one of the two
• Multi aperture plates 331 and 335 must be provided compared to the
• the deflection elements 334 are provided at all openings 339.
• deflection elements 334 are also at openings 339 of the second subsets of openings 339 of the plurality
• Multi aperture plates 331, 335 are provided.
• the deflection elements 334 of the second subset of openings 339 cannot be controlled by these deflection elements not being connected to the voltage sources or current sources 351 by line connections 349.
• FIG. 5 shows a further modification of the multi-aperture plate arrangement 305 explained with reference to FIGS. 2 to 4, which differs from the multi-aperture plate arrangement of FIGS. 2 to 4 in that the first and second subsets of openings are arranged on the multi-aperture plates.
• Figure 5 shows one
• FIG. 5 Top view of the first multi-aperture plate 331 with stigmators 333.
• Lines 361 in FIG. 5 each surround a group of openings 339 of a first subset of openings 339, which are provided with controllable deflection elements 334, while a second subset of openings 339 not surrounded by lines 361 controllable deflection elements does not have.
• the groups surrounded by the lines are arranged as arrow or boomerang-shaped figures.
• the associated second multi-aperture plate 335 which is not shown in the figures, has an arrangement of the openings 339 of the first subset which is complementary to the first subset shown in FIG.
• FIG. 6 is a schematic illustration of a plan view of deflection elements 334, which extends in the circumferential direction around a center 371 of an opening
• Multi aperture plate are arranged distributed.
• the deflection elements 334 together form a stigmator 333 for the targeted compensation of a
• the deflection elements are excited with excitations which are determined in such a way that the beam astigmatism is largely compensated for.
• FIG. 7 is a representation of deflection elements 334 corresponding to FIG. 6, although a deflection element designated 334 'is defective.
• the supply line to this deflection element 334 ' is interrupted, or the deflection element 334' is connected to ground, for example, or the like. If the deflection elements or electrodes 334 of FIG. 7 are the ones previously determined
• Electrode 334 'does not accept voltage V 4 . Rather, this electrode assumes a different voltage due to the defect, which is shown in FIG. 7 as V err
• FIG. 8 is an illustration of the deflection elements 334 of FIG. 7 with the defective deflection element 334 '. However, the deflection elements of FIG. 8 are excited with excitations that are modified compared to FIGS. 7 and 6. The
• modified excitations are determined by adding correction excitations to the previously determined excitations of FIG. 6.
• the electrodes 334 are supplied with voltages Vi + dV, V 2 + dV, ... V 8 + dV.
• the Correction excitations dV the same for all deflection elements.
• the value of the correction excitation dV is determined so that the following relation is fulfilled:
• V 4 + dV V err .
• the modified voltage to be supplied to the defective electrode 334 ' is equal to the voltage which the defective electrode assumes due to its defect, it is possible to actually excite the deflection elements with the modified excitations. There are also differences in excitement between individuals
• Stigmators 333 applied certain voltages increased by the value dV.
• the modified excitations on the beam passing through the defective stigmator 333 of FIG. 8 have an additional effect of a focusing lens compared to the beam passing through the intact stigmator 333 of FIG. In some situations, this additional effect can be a possibly disadvantageous effect on the beam, which can be accepted, since the advantageous effect of compensating the beam astigmatism outweighs the defective stigmator.
• a method for operating a particle beam device is explained below using the flow chart shown in FIG. 9.
• beam astigmatisms of the plurality of particle beams with which the multi-beam particle beam system works are determined in a step S1. This determination can be made on the basis of measurements which are carried out using the multi-beam particle beam system be made. However, it is also possible for the determination to be carried out on the basis of information which is stored, for example, in a database.
• a step S3 voltages are determined which are to be applied to electrodes of stigmators in order to compensate for the beam astigmatisms.
• a step S5 it is determined which stigmators are intact and which
• Stigmators are defective. This determination can in turn be carried out by measurements on the multi-beam particle beam system. Furthermore, it is possible that the intact and the defective stigmators are already known and
• Determinations in step S5 can be made by evaluating this information.
• the database can be kept, for example, outside the multi-beam particle beam system, in a controller of the multi-beam particle beam system or in a memory which is on or on the
• Multi-aperture plate with the stigmators is arranged.
• step S3 The voltages determined in step S3 are applied in step S7 to those stigmators which were identified in step S5 as intact stigmators.
• step S9 modified voltages are determined in step S9 by adding to the voltages determined in step S3
• step S9 The modified voltages determined in step S9 are applied to the defective stigmators in step S11.
• suitable voltages are applied to both the electrodes of the intact stigmators and the electrodes of the defective stigmators in order to suitably influence the particle beams passing through the stigmators in step S13. Then the multi-beam
• the multipole elements have eight deflection elements and are operated as stigmators.
• the explained principles of deviating the particular excitations are generally applicable to multipole elements which have at least two deflection elements arranged in the circumferential direction around a center.
• the deflection elements of the multipole elements are electrodes which are excited by the application of voltages in order to generate electric fields which deflect the particles of the particle beam passing through the multipole element.
• the variation of the particular excitations is also applicable to multipole elements whose deflection elements are coils that are excited by the application of currents to generate magnetic fields that deflect particles of the particle beam passing through the multipole element.
• FIG. 10 shows an array of 91 vectors 361.
• Each of the vectors 361 represents an influence on a particle beam which has an opening in a
• Multi-aperture plate 331 interspersed.
• the influencing is an astigmatic
• Influence and the vectors 361 represent the strength of the astigmatic influence by their length and the orientation of the astigmatic influence by their direction.
• the feet of the Vectors arranged at the center of a respective opening of the multi-aperture plate.
• the openings of the explained multi-aperture plate 331 are arranged in a hexagonal pattern.
• Each of the openings of the multi-aperture plate 331 comprises eight deflecting elements which are arranged circumferentially around the opening.
• Deflection elements can be supplied with adjustable excitations in order to provide an electrical and / or magnetic quadrupole field with a strength and an orientation in the opening such that one with regard to their strength and
• penetrating particle beam can take place.
• the vectors 361 have a large number of different lengths and different orientations.
• adjacent vectors often have lengths and orientations that do not differ greatly from one another.
• the deflection elements of adjacent openings are often supplied with the same excitation patterns, for the
• Deflection elements of these adjacent openings are used common feed lines.
• FIG. 11 shows two stigmators 333, each with eight deflection elements 343, each of which in the circumferential direction around a center 371 of an opening in the
• Multi-aperture plate 331 are arranged.
• the total number of deflection elements 343 of the two stigmators 333 is therefore sixteen. These sixteen deflection elements 343 are only excited by a voltage supply system 351 eight leads 363 supplied.
• the leads 363 can be formed on the surface of the multi-aperture plate.
• Feed lines are formed in two conductive layers on a substrate of the multi-aperture plate, the conductive layers being insulated from one another and electrically conductive connections being able to be produced between the two layers.
• FIG. 12 is a representation of the field of vectors 361 corresponding to FIG. 10 and additionally represents the assignment of openings of the
• Multi aperture plate 331 to groups 365 of openings.
• No opening belongs to two different groups 365. Not all openings have to belong to a group 365. For example, seven openings, which are arranged near the center of the multi-aperture plate 331, do not belong to any of the groups 365.
• the division of the openings into the groups 365 is selected such that the vectors 361 of openings of the same group 365 do not differ greatly from one another in terms of their length and their orientation. Two to three openings are each contained in a group 365. Since the vectors 361 of each group 365 do not differ greatly from one another in terms of their length and orientation, provision is made for the deflection elements of openings in each group to be supplied with excitation by common feed lines, as is the case in FIG Openings is shown. It is then possible, at each opening of a given group 365, to influence the particle beam passing through the opening not exactly, but almost as is ideally desired and as represented by the array of vectors 361 in FIG. 10. It has been shown that the division of the openings of a multi-aperture plate into groups, as is shown by way of example in FIG. 12, can be maintained in many application situations of a multi-beam particle beam system.
• the division of the openings of a multi-aperture plate into groups can be maintained in many application situations of a
• Application situations can differ, for example, with regard to the kinetic energy of the particle beams passing through the openings of the multi-aperture plate or the particle beams directed at an object in the beam path behind the multi-aperture plate. For several different kinetic energies, an equal division of the opening of the
• Multi-aperture plates in groups lead to a good result of the ability to influence the particle beams. This means that it can make sense to define the supply of excitation to the deflection elements of a multi-aperture plate by means of common supply lines in the manufacture of the multi-aperture plate, to integrate the multi-aperture plate in a multi-beam partial beam system, and then to use the multi-beam particle beam system in a variety of situations use.

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• 2018
  • 2018-10-01 DE DE102018124219.0A patent/DE102018124219A1/de active Pending
• 2019
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