DE102008064786B3 - Procedure for analyzing a sample - Google Patents

Abstract

A method of analyzing a sample (11, 26) having a sample surface, the method comprising the steps of:- identifying a portion (26) of the sample (11) to be analyzed including locating a location of particular interest on the sample surface;- generating a first interface (27) between the part (26) to be analyzed of the sample (11) and the sample (11) at a distance from the point of particular interest, the first interface (27) being at an angle other than 0° and 180° to the sample surface;- creating a second parting surface (29) between the part (26) of the sample (11) to be analyzed and the sample (11), the second parting surface (29) being at an angle deviating from 0° and 180° to the sample surface and wherein the second interface (29) contains the site of particular interest;- polishing only the second interface (29) by means of a particle beam;- separating the part (26) of the sample (11) to be analyzed from the sample (11) by generating further separating surfaces;- aligning the second separating surface (29) perpendicularly or substantially perpendicularly to the optical axis of a particle beam device; and- analyzing the second interface (29) by detecting particles leaving the part (26) to be analyzed on the side of the second interface (29),- wherein at least the step of polishing the second interface (29) and the step the analysis of the second parting surface (29) takes place in the same vacuum chamber (6) without the part (26) to be analyzed being discharged from the vacuum chamber (6) between the two steps.

Description

The invention relates to a method for analyzing a sample, in particular a method which is used in a particle beam device.

In particular in the field of material analysis, for example in semiconductor technology, it is necessary to create cross sections of a sample and examine them more closely.

For this purpose, a method is known from the prior art in which a sample is first prepared and then examined in a particle beam device. The sample is prepared in a first particle beam device, which has both an electron beam column and an ion beam column. A part of the sample to be analyzed is first identified by means of an electron beam, which is made available by the electron beam column. This part of the sample to be analyzed is then prepared using an ion beam provided by the ion beam column and cut out of the sample. The part of the sample that has been cut out and to be analyzed is then channeled out of the first particle beam device and then channeled back into a second particle beam device in the form of a transmission electron microscope. Further investigations are then carried out on the part of the sample to be analyzed using the second particle beam device.

A disadvantage of this known method, however, is that the part of the sample to be analyzed must be discharged from the first particle beam device and introduced into the second particle beam device. It is quite possible that the part of the sample to be analyzed becomes so contaminated that further examination using the second particle beam device (transmission electron microscope) can no longer be carried out. In addition, the expenditure of time is quite high due to the ejection. Furthermore, there is always the risk that the part of the sample to be analyzed will be damaged during ejection, so that it can no longer be examined further.

With the above-mentioned method, it would be conceivable to also examine the part of the sample to be analyzed in the first particle beam device, so that the part of the sample to be analyzed does not have to be discharged from the first particle beam device. However, only one examination is then possible, which provides an unsatisfactory spatial resolution. For geometric reasons, the part of the sample to be analyzed can only be viewed from an oblique angle in the first particle beam device. Basically, a beam of particles is directed at the part of the sample to be analyzed at an oblique angle. This definitely degrades the spatial resolution. In addition, an image of the part of the sample to be analyzed can also be distorted.

A further method for analyzing a sample is known from the prior art, which is carried out in a vacuum chamber of a single particle beam device and in which it is not necessary to discharge and reinsert a sample. In this known method, a part of a sample to be analyzed is cut out of the sample by means of an ion beam. After cutting out, the part to be analyzed is attached to a holder and lifted out of the sample. The extracted part of the sample to be analyzed is attached to an object holder in order to then be examined using an electron beam. During the examination, electrons transmitted through the part of the sample to be analyzed are detected. The detected transmitted electrons are used to draw conclusions about the material of the part of the sample to be analyzed.

With regard to the aforementioned prior art is on the U.S. 6,963,068 B2 referred.

Reference is also made to the publication by GNAUCK, P; HOFFROGGE, P. with the title "New SEM/FIB crossbeam inspection tool for high-resolution materials and device characterization" in Proceedings of SPIE, 2003, volume 4980 (1), pp. 106-113 (ISBN 9780819447807), to the publication von LANGFORD, Richard M. entitled "Focused ion beams techniques for nanomaterials characterization" in Microscopy research and technique, Vol. 69, 2006, pp. 538-549 (ISSN 0741-0581), the U.S. 6,570,170 B2 , the DE 10 2007 026 847 A1 , the U.S. 7,408,178 B2 , the U.S. 6,664,552 B2 , the U.S. 6,570,170 B2 , the U.S. 6,188,068 B1 as well as the U.S. 5,270,552 A referred.

The known methods described above have in common that the sample is analyzed in transmission. As a result, the production of the sample or the part of the sample to be analyzed is very complex, since the sample has to be produced in the form of a thin sample lamella with a thickness of only a few nm, which must then also contain the part of the sample that is currently of interest.

It is therefore the object of the invention to specify a method which allows simpler production of the part of the sample to be analyzed and enables simplified analysis.

This object is achieved by means of a method having the features of claim 1.

Further features of the invention result from the following description, the following claims and/or the attached figures.

In the method according to the invention, a sample is provided which is composed of at least one sample material. First, a portion of the sample to be analyzed is identified. An opening is then made in the sample material by means of a particle beam in such a way that the opening at least partially adjoins the part of the sample to be analyzed. Furthermore, the opening is designed in such a way that at least one surface of the part of the sample to be analyzed can be completely accommodated in the opening. Furthermore, the method according to the invention comprises separating the part of the sample to be analyzed from the sample material by means of the particle beam. The part of the sample to be analyzed can then be examined more closely.

In a method according to the present invention, a portion of the sample to be analyzed and removed from the sample can be analyzed by detecting the particles backscattered from the portion of the sample to be analyzed or particles emitted from the portion of the sample to be analyzed. Particles emitted by the part of the sample to be analyzed are to be understood as meaning particles that differ significantly from the kinetic energy of the particles in the particle beam impinging on the part of the sample to be analyzed, at least with regard to their kinetic energy, in particular a kinetic energy below 100 eV exhibit. With the method according to the invention it is possible, for the analysis of the part of the sample to be analyzed, to detect only those particles which emerge essentially on the side of the part of the sample to be analyzed on which the particle beam impinges. As a result, the part of the sample to be analyzed can have a significantly greater thickness than in methods in which the particles transmitted through the sample are detected. This makes the production of the part of the sample to be analyzed with the cross-section of the sample of interest less critical and simpler.

Furthermore, in a method according to the invention, the part of the sample to be analyzed can be analyzed in the same sample chamber or vacuum chamber in which the processing and thus the removal of the part of the sample to be analyzed from the sample also takes place.

The invention therefore has the advantage that the part of the sample to be analyzed does not have to be discharged from the particle beam device after it has been separated from the sample material in order to be examined further. This avoids contaminating the part of the sample to be analyzed before an examination. In contrast to the prior art, in which an ejection is provided, less time is required. In addition, there is less risk of the part of the sample to be analyzed being damaged, which can certainly happen during a discharge process. Furthermore, it is advantageous in the method according to the invention that particles scattered back from the part of the sample to be analyzed and/or emitted particles can be detected and used for the analysis. In particular, backscattered electrons (backscattered electrons) and/or emitted electrons (secondary electrons) are detected. In addition, the part of the sample to be analyzed can always be irradiated with a particle beam for examining the part to be analyzed in such a way that the particle beam can be applied perpendicularly or essentially perpendicularly to the part of the sample to be analyzed. The part of the sample to be analyzed does not have to be tilted and is not at an angle to the incident particle beam. In this way, a high spatial resolution is achieved. Furthermore, image distortions, which have already been described above, are avoided.

In a first embodiment of the method according to the invention, the particle beam that is provided to produce the opening is provided as a first particle beam. Furthermore, the part of the sample to be analyzed is placed on a sample holder. The part of the sample to be analyzed is then examined using a second particle beam. For this purpose, the sample holder is moved, for example, in such a way that the second particle beam hits the part of the sample to be analyzed perpendicularly or essentially perpendicularly. In addition, it is provided, if necessary, to further process the part of the sample to be analyzed before an examination, for example by means of the first particle beam. In yet another embodiment, provision is made for the part of the sample to be analyzed to first be arranged on a manipulation device, with which the part of the sample to be analyzed is lifted out of the sample material. This is followed by the arrangement on the sample holder.

In a further embodiment of the method according to the invention, provision is also made for the particle beam used to produce the opening to be in the form of a first particle beam. In this embodiment, a Placing the part of the sample to be analyzed in the opening in the sample material. This is followed by an examination of the part of the sample to be analyzed using a second particle beam. The part of the sample to be analyzed is arranged in the opening in such a way that a surface of the part of the sample to be analyzed that corresponds to a cross-sectional area of the sample, i.e. corresponds to a cut surface that is oriented essentially perpendicular to the sample surface, in the opening is oriented substantially parallel to the surface of the sample. Due to this arrangement in the opening, the particle beam can be fed to the part of the sample to be analyzed during the analysis of the part of the sample to be analyzed in such a way that the particle beam is perpendicular or essentially perpendicular to the surface of the sample that corresponds to the cross-sectional area of the sample analyzed part of the sample can occur.

Furthermore, the method according to the invention provides for an ion beam to be used as the first particle beam and/or an electron beam to be used as the second particle beam. In particular, it is provided that the opening is made in the sample material by means of the ion beam and that the part of the sample to be analyzed is separated from the sample material. The part of the sample to be analyzed is then examined more closely by means of the electron beam. The secondary particles produced by an interaction of the electron beam with the sample material, in particular electrons scattered back from the sample material or electrons emitted, are detected.

It is explicitly pointed out that the first particle beam and the second particle beam do not necessarily have to be designed differently from one another. Rather, embodiments of the method according to the invention are also provided in which the first particle beam and the second particle beam are configured identically, for example as an ion beam. In this embodiment, the opening in the sample material is made by means of the ion beam and the part of the sample to be analyzed is separated from the sample material by means of the ion beam. By directing the ion beam to the part of the sample to be analyzed, secondary ions are generated, which are then analyzed by mass spectrometry, for example, in order to draw conclusions about the material of the sample.

In a further embodiment of the method according to the invention, the part of the sample to be analyzed is identified by means of the second particle beam. If the second particle beam is in the form of an electron beam, images of the sample can be calculated and displayed using the detected backscattered electrons or the emitted electrons, on the basis of which the identification can take place.

The arrangement of the part of the sample to be analyzed in the opening in the sample material takes place, for example, at least partly due to the force of gravity. This embodiment of the method according to the invention is based on the consideration that the part of the sample to be analyzed can be separated from the sample material in such a way that the part of the sample to be analyzed falls into the opening made in the sample material by itself due to gravity. However, it is explicitly pointed out that the invention is not restricted to an arrangement of the part of the sample to be analyzed in the opening by means of gravity. Rather, the part of the sample to be analyzed can be arranged in the opening of the sample in any way that is suitable for this purpose. For example, in a further embodiment of the method according to the invention, it is provided that the part of the sample to be analyzed is pushed into the opening made in the sample material by means of a manipulator device.

In a further embodiment of the method according to the invention, it is provided that the part of the sample to be analyzed is separated from the opening. Then the part of the sample to be analyzed is placed in the opening or falls into the opening. In addition, it can be provided that the part of the sample to be analyzed is then arranged on the sample holder already mentioned above. As will be explained in more detail below, one embodiment of the invention provides for several openings to be made in the sample material. For example, it is provided to introduce a first opening and a second opening in the sample material. The first opening is designed to accommodate the part of the sample to be analyzed. The second opening is formed smaller than the first opening. In this embodiment, the part of the sample to be analyzed is separated from the first opening. A further embodiment provides for the dimensions of both the first opening and the second opening to be essentially identical. In this embodiment one can select whether the part of the sample to be analyzed is received in the first opening or in the second opening. In this embodiment, the separation takes place from that opening in which the part of the sample to be analyzed is to be arranged.

In a further embodiment of the method according to the invention by separating the part of the sample to be analyzed from the Sample material produces at least one cut surface, which is initially arranged perpendicularly or substantially perpendicularly to a surface of the sample. When the part of the sample to be analyzed is arranged in the opening, the cut surface is introduced in such a way that the cut surface is arranged parallel or essentially parallel to the surface of the sample. In this way it is then easily possible to examine the cut surface by means of the particle beam. In particular, it is possible to examine the cut surface under perpendicular irradiation by means of the particle beam. When using a first particle beam and a second particle beam, the cut surface is examined by means of the second particle beam, for example. In a further exemplary embodiment, provision is made for the cut surface to be prepared, in particular polished, by means of the particle beam before the part of the sample to be analyzed is arranged in the opening. During the preparation, the cut surface is aligned essentially parallel to the incident particle beam. When using a first particle beam and a second particle beam, the first particle beam is used for the preparation, for example.

In a further embodiment of the invention, at least one cut surface is produced by separating the part of the sample to be analyzed from the sample material. After arranging the part to be analyzed on the sample holder, the cut surface is then positioned in such a way that the particle beam is incident perpendicularly on the cut surface. When using a first particle beam and a second particle beam, for example, the second particle beam falls perpendicularly onto the cut surface. In this embodiment of the invention, too, provision can be made for the cut surface to be prepared, in particular polished, before the particle beam is applied to the cut surface.

In a further embodiment of the invention, it is provided that the part of the sample to be analyzed is separated in such a way that the part of the sample to be analyzed has a first extension in a first direction, a second extension in a second direction and a third extension in one third direction. The first and second directions extend parallel to a surface of the sample, and the third direction extends perpendicularly to this surface. The first and the third dimension form the length and the width of the part of the sample to be analyzed. For example, the second extent in the second direction is 1 μm to 20 μm, or else 5 μm to 15 μm. The second dimension corresponds to the thickness of the part of the sample to be analyzed. It is designed in such a way that no interaction particles are transmitted through the sample when it is irradiated with a particle beam and the sample is so stable that it does not break easily. Consideration has shown that the part of the sample to be analyzed has a length of about 10 μm to about 200 μm, a width of about 5 μm to about 100 μm and a thickness of about 0.5 μm to 20 μm. However, the invention is not limited to the aforementioned extensions of the part of the sample to be analyzed. Rather, any expansion that is suitable for carrying out the method according to the invention can be used. One embodiment of the invention also provides for the detection and evaluation of interaction particles transmitted through the sample.

In one embodiment of the method according to the invention, the opening is produced in the sample material in such a way that the opening has a first opening extent in the first direction, a second opening extent in the second direction and a third opening extent in the third direction. The first direction and second direction in turn extend parallel to a surface of the sample, the third direction extends perpendicularly to this surface. The first opening extent is greater than or equal to the first extent of the part of the sample to be analyzed. Furthermore, the second opening dimension is formed larger than the second dimension of the part of the sample to be analyzed. The third opening extent is in turn greater than or equal to the third extent of the part of the sample to be analyzed. The aforementioned opening dimensions are always selected in such a way that the part of the sample to be analyzed can be accommodated in the opening in the sample without any problems. In particular, the first opening dimension is also larger than the third dimension of the part of the sample to be analyzed. The part of the sample to be analyzed can then be examined sufficiently well. In a further embodiment, the part of the sample to be analyzed is received entirely in the opening in the sample material.

In a further embodiment of the method according to the invention, a plurality of openings are provided. Thus, the opening already described above is designed as a first opening which borders on a first side of the part of the sample to be analyzed. Additionally, in separating the sample portion to be analyzed from the sample material, a second opening is also made, the second opening being positioned on a second side of the sample portion to be analyzed, opposite the first side of the sample portion to be analyzed. It is also envisaged that the second side of the to be analyzed or second particle beam, respectively. Basically, the second side, which is examined in more detail by means of the particle beam or the second particle beam, is only uncovered relatively late. Thus, the risk of the second side becoming contaminated is reduced. The second side can correspond to the above cut surface.

The invention also relates to a method for analyzing a sample, in which a sample is provided which is composed of at least one sample material. First, a portion of the sample to be analyzed is identified. An opening is then introduced into the sample material by means of a first particle beam in such a way that the opening at least partially adjoins the part of the sample to be analyzed. Furthermore, the method according to the invention includes separating the part of the sample to be analyzed from the sample material by means of the first particle beam. After the separation, the part of the sample to be analyzed is placed in the opening in the sample material. The part of the sample to be analyzed is then examined using a second particle beam. The method described above is based on the same basic idea as the method already described above. It can also be combined with any of the features or combinations of features mentioned above.

The invention also relates to a particle beam device for carrying out a method, which has one of the features mentioned above or a combination of the features mentioned above. The particle beam device has a sample composed of at least one sample material. At least one means for identifying a part of the sample to be analyzed is also provided. The means includes, for example, an electron beam column that provides an electron beam. A surface of the sample can be imaged by detecting the particles generated by the interaction of the electron beam with the sample material.

In addition, at least one means for producing an opening in the sample material by means of a first particle beam is provided in the particle beam device, the opening at least partially adjoining the part of the sample to be analyzed. Furthermore, at least one means is provided for separating the part of the sample to be analyzed from the sample material by means of the first particle beam. At least one means for examining the part of the sample to be analyzed by means of a second particle beam is also provided.

The invention also relates to a method for analyzing a sample that has a sample surface. The method includes the step of identifying a part of the sample to be analyzed including finding a particularly interesting location on the sample surface. Provision is also made for creating a first interface between the part of the sample to be analyzed and the sample at a distance from the site of particular interest, with the first interface being at an angle to the sample surface that differs from 0° and 180°. A second interface is also created between the part of the sample to be analyzed and the sample, the second interface being at an angle to the sample surface that differs from 0° and 180° and the second interface containing the location of particular interest. The method also comprises the step of polishing only the second interface by means of a particle beam and the step of separating the part of the sample to be analyzed from the sample by creating further interfaces. The method also provides for the second separating surface to be aligned perpendicularly or essentially perpendicularly to the optical axis of a particle beam device. Furthermore, the method provides for an analysis of the second interface using the detection of particles which leave the part to be analyzed on the side of the second interface. At least the step of polishing the second parting surface and the step of analyzing the second parting surface takes place in the same vacuum chamber without the part to be analyzed being discharged from the vacuum chamber between the two steps.

In a further embodiment of the aforementioned method, provision is made for the second separating surface to be scanned with a focused particle beam in order to analyze it. In a further embodiment of the method, an electron beam or an ion beam is used as the focused particle beam. The focused particle beam provides a spatial resolution perpendicular to its beam direction of less than 5 nm, in particular less than 1 nm.

Commercially available scanning electron microscopes allow electron probes whose diameters are so small that the achievable resolution perpendicular to the direction of incidence of an electron beam is less than 5 nm, sometimes even below 1 nm, especially when the surface of the sample to be analyzed is aligned perpendicular to the optical axis of the device and can be positioned at a sufficiently small working distance of a few (1-5) mm from the objective of the scanning electron microscope. The inventive method described above can therefore without Problems can be performed with conventional scanning electron microscopes.

• 1 eine schematische Darstellung eines Teilchenstrahlgeräts zur Durchführung eines Verfahrens zur Analyse einer Probe;
• 1A eine weitere schematische Darstellung des Teilchenstrahlgeräts nach 1;
• 2 ein Ablaufdiagramm eines Ausführungsbeispiels des Verfahrens;
• 3 eine schematische Darstellung einer Probe;
• 4 eine weitere schematische Darstellung der Probe gemäß 3, wobei die Probe eine Öffnung aufweist;
• 5 eine weitere schematische Darstellung der Probe gemäß 3, wobei die Probe zwei Öffnungen aufweist;
• 6 eine weitere schematische Darstellung der Probe gemäß 3, wobei ein zu analysierender Teil der Probe zur Trennung von der Probe vorbereitet ist;
• 7 eine weitere schematische Darstellung der Probe gemäß 3, wobei der zu analysierende Teil der Probe in der Öffnung angeordnet ist;
• 8A,B eine schematische Darstellung eines weiteren Verfahrens zur Analyse einer Probe; sowie
• 9 eine schematische Darstellung eines weiteren Teilchenstrahlgeräts zur Durchführung eines Verfahrens zur Analyse einer Probe.

The invention will now be explained in more detail on the basis of exemplary embodiments using figures. show it

• 1 a schematic representation of a particle beam device for carrying out a method for analyzing a sample;
• 1A a further schematic representation of the particle beam device 1 ;
• 2 a flowchart of an embodiment of the method;
• 3 a schematic representation of a sample;
• 4 a further schematic representation of the sample according to FIG 3 , wherein the sample has an aperture;
• 5 a further schematic representation of the sample according to FIG 3 , wherein the sample has two openings;
• 6 a further schematic representation of the sample according to FIG 3 wherein a portion of the sample to be analyzed is prepared for separation from the sample;
• 7 a further schematic representation of the sample according to FIG 3 wherein the portion of the sample to be analyzed is placed in the aperture;
• 8A,B a schematic representation of a further method for analyzing a sample; as well as
• 9 a schematic representation of a further particle beam device for carrying out a method for analyzing a sample.

1 and 1a show a schematic representation of a particle beam device, which has an ion beam device 1 and an electron beam device 24, which are arranged on a sample chamber 6 (vacuum chamber). The method according to the invention, which is explained in more detail further below, is carried out with the particle beam device shown. First, the particle beam device is explained in more detail.

The ion beam device 1 has an ion beam column 2 in which numerous units of the ion beam device 1 are arranged. In particular, an ion source 3 is arranged in the ion beam column 2 . Ions are generated with the ion source 3 and form an ion beam in the ion beam column 2 . The ions are accelerated to a predeterminable potential by means of an electrode 4 and then passed through a condenser lens 5 . The ion beam formed from the ions is passed through a diaphragm 7 and then reaches a first deflection arrangement 8 and a second deflection arrangement 9, which are designed as raster means. The ion beam consisting of the ions is scanned over a sample 11 arranged in the sample chamber 6 by means of the first deflection arrangement 8 and the second deflection arrangement 9 . Beforehand, the ion beam is focused onto the sample 11 by means of an objective lens 10 .

The electron beam device 24 is designed as a scanning electron microscope. It has an electron column 16 in which the units of the electron beam device 24 are arranged. An electron source 17 is provided, which generates electrons which are extracted by means of a first electrode 18 . The electrons are accelerated to a predeterminable potential by means of a second electrode 19 . The electrons are then passed through a condenser lens 20, forming an electron beam. This is focused onto the sample 11 by means of an objective lens 21 . Scanning electrodes (not shown) arranged on the objective lens 21 ensure that the electron beam can be scanned over the sample 11 .

Interaction particles, in particular secondary electrons and backscattered electrons (above and below also referred to as backscattered electrons), are formed when the electron beam impinges on the sample 11 . These are detected by a first detector 22 and by a second detector 23 and used for imaging. It is thus possible to image the surface of the sample 11.

In 2 the sequence of an embodiment of the method according to the invention, which can be carried out with the aforementioned particle beam device, is shown schematically. First, the sample 11 is brought into a second sample position B in a first method step S1. In this second sample position B, an electron beam generated in method step S2 hits the surface of the sample 11 perpendicularly. This makes it possible to provide an image of the surface of the sample 11 by detecting secondary electrons and/or backscattered electrons which, due to the interaction of the sample material are generated with the impinging electron beam (method step S3).

In a further method step S4, a part 26 of the sample 11 to be analyzed is then identified on the basis of the image. In particular, a site of particular interest in which to be analyzed sizing part 26 of the sample 11 identified. Sample 11 is in 3 shown again schematically.

The sample 11 is then brought into a first sample position A (method step S5). In the first sample position A, an ion beam generated by the ion beam device 1 hits the sample 11 perpendicularly. Then, in a method step S6, a first opening 25 is made in the material of the sample 11 by means of the ion beam (cf. also 4 ). For this purpose, the ion beam is scanned over the material of the sample 11. In addition, the sample 11 can be moved by means of a movably designed sample table (not shown), on which the sample 11 is arranged. The first opening 25 is adjacent to a first side 27 of the part 26 to be analyzed of the sample 11 and has a first opening dimension O1 in a first direction, a second opening dimension O2 in a second direction and a third opening dimension O3 in a third direction (cf . 4 ). The direction vectors belonging to the individual directions are perpendicular to one another. The first side 27 of the part 26 of the sample 11 to be analyzed is offset by the desired thickness of the part 26 of the sample 11 to be analyzed from the location of particular interest identified in method step S4.

In a further method step S7, a second opening 28 is made in the sample material of the sample 11 by means of the ion beam (cf. also 5 ). The second opening 28 is located adjacent a second side 29 of the portion 26 of the sample 11 to be analyzed, which is opposite the first side 27 of the portion 26 of the sample 11 to be analyzed. The second side 29 of the part 26 of the sample 11 to be analyzed is as close as possible and ideally contains the location of particular interest identified in method step S4.

The second opening 28 has an opening size O4 in the first direction, an opening size O5 in the second direction, and an opening size O6 in the third direction. The opening dimension O5 of the second opening 28 is significantly smaller than the second opening dimension O2 of the first opening 25. In contrast, the opening dimension O6 of the second opening 28 is slightly larger than the opening dimension O3 of the first opening 25. In another embodiment (not shown), the first opening 25 and the second opening 28 are dimensioned identically.

In a further method step S8, the second side 29 is prepared by polishing using the ion beam. The sample 11 is then brought into a third sample position C (method step S9), in which the sample 11 is in the in 2 illustrated embodiment is arranged tilted about 10 ° to 20 ° from the vertical (cf. 1 ). In a further method step S10, a lower surface 31 of the part 26 of the sample 11 to be analyzed is then separated from the sample material (cf. 6 ). For this purpose, the ion beam is guided from the direction of the first opening 25 to the part 26 to be analyzed and the part 26 of the sample 11 to be analyzed is separated.

The sample 11 is then returned to the first sample position A (method step S11). In this first sample position A, the part 26 of the sample 11 to be analyzed is now separated at its side surfaces 30 from the sample material of the sample 11 (cf. 6 ). The ion beam is used again for this purpose (method step S12).

The part 26 of the sample 11 to be analyzed falls into the first opening 25 by gravity (method step S13). As an alternative to this, the part 26 of the sample 11 to be analyzed can also be pushed into the first opening 25 by means of a manipulator device. In both alternatives, the part 26 of the sample 11 to be analyzed is arranged in such a way that the second side 29 is not covered and can be examined with a particle beam. The second side 29 of the part 26 to be analyzed of the sample 11 is tilted by about 90° in the first opening 25 compared to the original orientation of the second side 29 of the part 26 to be analyzed of the sample 11. As a result, a surface of the part 26 to be analyzed is located of the sample 11, which corresponds to a cross-sectional area through the sample 11, parallel to the sample surface and can thus be analyzed using a particle beam incident perpendicularly or almost perpendicularly on this cross-sectional area (cf. 7 ). It is advantageous that the second side 29 of the part 26 of the sample 11 to be analyzed is exposed relatively late. Thus, the risk of the second side 29 becoming contaminated is reduced.

The part 26 to be analyzed produced using the above-mentioned method has a dimensioning as already mentioned above. The portion 26 of the sample 11 to be analyzed produced in this embodiment is in the form of a lamella. The aforesaid dimensions of the part 26 of the sample 11 to be analyzed are so large that it can easily be produced by means of the ion beam. Furthermore, they are dimensioned in such a way that the part 26 to be analyzed can be accommodated in the first opening 25 . Furthermore, no interaction particles are transmitted through the part 26 of the sample 11 to be analyzed. Rather, another Investigation method applied as explained below.

To examine the second side 29, the sample 11 is brought into the second sample position B, in which the electron beam can fall perpendicularly onto the second side 29 of the part 26 of the sample 11 to be analyzed (method steps S14 and S15). The interaction of the sample material and the electron beam creates secondary electrons and backscattered electrons that are detected. The signals obtained by the detection are analyzed and evaluated in a further method step S16, in particular for imaging.

As the exemplary embodiment of the method according to the invention shows, the electron beam is fed perpendicularly or essentially perpendicularly onto the part 26 of the sample 11 to be analyzed. The part 26 of the sample 11 to be analyzed is therefore not at an oblique angle to the incident electron beam. In this way, a high spatial resolution is achieved. Furthermore, image distortions, which have already been described above, are avoided.

In a further embodiment of the method, it is additionally provided that the part 26 of the sample 11 to be analyzed is examined by means of secondary ion mass spectroscopy (SIMS). To this end, a further method step is introduced after method step S16, for example. In this further method step, the sample 11 is brought back into the first sample position A. When the ion beam impinges on the surface of the part 26 of the sample 11 to be analyzed, secondary ions are generated which are analyzed by mass spectrometry. For this purpose, an ion mass analyzer 12 is provided, which generates a mass spectrum. The generated mass spectrum is then compared with a large number of mass spectra which are stored in a storage unit 14 of a control unit 13 . The comparison of the generated mass spectrum with the stored mass spectra is carried out using the processor 15 of the control unit 13 . In this way it is possible to determine the material from which the sample 11 is composed.

The 8A and 8B show a further embodiment of the method according to the invention, which can be carried out with the particle beam device described above. The exemplary embodiment now described is based on the method described in 2 is shown schematically and on the sample, which in the 3 until 7 is shown. The method steps S1 to S7 correspond to the 8A and 8B the method steps S1 to S7 of the method according to 2 , so that reference is made to the explanations given above with regard to these method steps.

In contrast to the method according to the 2 After method step S7, method step S17 follows, in which the sample 11 is brought into the third sample position C. Subsequently, in a further method step S18, a lower surface 31 of the part 26 of the sample 11 to be analyzed is separated from the sample material. For this purpose, the ion beam is guided from the direction of the first opening 25 to the part 26 to be analyzed and the part 26 of the sample 11 to be analyzed is separated. Thereafter, the sample 11 is brought to the first sample position A (step S19).

In a further method step S20, the part 26 of the sample 11 to be analyzed is arranged on a manipulation device. The manipulation device is designed, for example, as a micromanipulator. The part 26 of the sample 11 to be analyzed is arranged, for example, by means of gas deposition or by means of mechanical clamps. The side surfaces 30 of the part 26 of the sample 11 to be analyzed are then separated from the sample material by means of the ion beam (method step S21) and the part 26 of the sample 11 to be analyzed is lifted out of the sample material (method step S22).

The part 26 of the sample 11 to be analyzed is now brought to a sample holder and arranged on it (method step S23). The part 26 of the sample 11 to be analyzed is arranged on the sample holder here by means of gas deposition or by means of mechanical clamps. In a subsequent method step S24, the side 29 of the part 26 to be analyzed of the sample 11, which is to be examined in the further method by means of the electron beam, is now prepared by polishing.

The sample holder is designed to be movable so that it can position the part 26 of the sample 11 to be analyzed that is now attached to the sample holder (method step S25). The positioning is carried out in such a way that an electron beam generated in method step S26 strikes the side 29 of the part 26 of the sample 11 to be analyzed perpendicularly or at least essentially perpendicularly. The resulting secondary electrons and backscattered electrons are detected. The signals obtained by the detection are analyzed and evaluated in a further method step S27, in particular for imaging. If necessary, method steps S25 to S27 are repeated. This is checked in method step S28.

9 shows a further embodiment of a particle beam device with which the method described above can be carried out. It basically differs from the embodiment according to FIG 1 only in that the ion beam device 1 and the electron beam device 24 are arranged parallel to one another and in each case vertically.

The sample 11 is moved back and forth between a first sample position A below the ion beam device 1 and a second sample position B below the electron beam device 24 . In order to produce the part 26 of the sample 11 to be analyzed, the sample 11 is mounted in the first sample position A in such a way that it can be tilted.

Reference List

1

ion beam device

2

ion beam column

3

ion source

4

electrode

5

condenser lens

6

sample chamber/vacuum chamber

7

cover

8th

first deflection arrangement

9

second deflection arrangement

10

objective lens

11

sample

12

ion mass analyzer

13

control unit

14

storage unit

15

processor

16

electron column

17

electron source

18

first electrode

19

second electrode

20

condenser lens

21

objective lens

22

first detector

23

second detector

24

electron beam device

25

first opening

26

part to be analyzed

27

first page

28

second opening

29

second page

30

side faces

31

lower surface

O1

Opening expansion first opening in first direction

O2

Opening extension first opening in second direction

O3

Opening expansion first opening in third direction

O4

Opening extension second opening in first direction

O5

Opening expansion second opening in second direction

O6

Opening extension second opening in third direction

A

first sample position

B

second sample position

C

third sample position

Claims (3)

A method of analyzing a sample (11, 26) having a sample surface, the method comprising the steps of: - identifying a portion (26) of the sample (11) to be analyzed including locating a location of particular interest on the sample surface; - creating a first interface (27) between the part (26) to be analyzed of the sample (11) and the sample (11) at a distance from the point of particular interest, the first interface (27) being at one of 0° and 180° ° deviating angle to the sample surface; - Creating a second interface (29) between the part (26) of the sample (11) to be analyzed and the sample (11), the second interface (29) being at an angle deviating from 0° and 180° to the sample surface and wherein the second interface (29) contains the point of interest; - Polishing only the second parting surface (29) by means of a particle beam; - Separating the part (26) of the sample (11) to be analyzed from the sample (11) by generating further separating surfaces; - Aligning the second separating surface (29) perpendicularly or substantially perpendicularly to the optical axis of a particle beam device; and - analyzing the second interface (29) by detecting particles leaving the part (26) to be analyzed on the side of the second interface (29), - wherein at least the step of polishing the second interface (29) and the step of analysis Sierens the second separating surface (29) in the same vacuum chamber (6), without the part (26) to be analyzed being discharged from the vacuum chamber (6) between the two steps. procedure after claim 1 , in which the analysis of the second interface (29) this is scanned with a focused particle beam. procedure after claim 2 , in which an electron beam or an ion beam is used as the focused particle beam and in which the focused particle beam provides a spatial resolution perpendicular to its beam direction of less than 5 nm, in particular less than 1 nm.

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