U.S. patent application number 12/175940 was filed with the patent office on 2009-01-22 for charged particle beam apparatus, and sample processing and observation method.
This patent application is currently assigned to HITACHI HIGH-TECHNOLOGIES CORPORATION. Invention is credited to Hiroyuki MUTO, Tsuyoshi Ohnishi, Isamu Sekihara.
Application Number | 20090020698 12/175940 |
Document ID | / |
Family ID | 40264074 |
Filed Date | 2009-01-22 |
United States Patent
Application |
20090020698 |
Kind Code |
A1 |
MUTO; Hiroyuki ; et
al. |
January 22, 2009 |
CHARGED PARTICLE BEAM APPARATUS, AND SAMPLE PROCESSING AND
OBSERVATION METHOD
Abstract
An object of the present invention relates to realizing the
processing of a sample by charged particle beams and the monitoring
of the processed cross-section with a high throughput. It is
possible to process an accurate sample without an intended region
lost even when the location and the size of the intended region are
unknown by: observing a cross-sectional structure being processed
by FIBs by using a secondary particle image generated from a sample
by the ion beams shaving a cross section; forming at least two
cross sections; and processing the sample while the processing and
the monitoring of a processed cross section are carried out.
Inventors: |
MUTO; Hiroyuki;
(Hitachinaka, JP) ; Ohnishi; Tsuyoshi;
(Hitachinaka, JP) ; Sekihara; Isamu; (Hitachinaka,
JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
HITACHI HIGH-TECHNOLOGIES
CORPORATION
|
Family ID: |
40264074 |
Appl. No.: |
12/175940 |
Filed: |
July 18, 2008 |
Current U.S.
Class: |
250/310 ;
250/492.21; 250/492.3 |
Current CPC
Class: |
H01J 37/3056 20130101;
H01J 2237/31749 20130101; H01J 2237/30466 20130101; H01J 2237/31745
20130101; G01N 1/32 20130101; H01J 37/3045 20130101; H01J 2237/2806
20130101; H01J 37/3005 20130101; H01J 2237/31713 20130101; H01J
37/244 20130101; H01J 2237/2448 20130101; H01J 37/28 20130101 |
Class at
Publication: |
250/310 ;
250/492.21; 250/492.3 |
International
Class: |
G01N 23/225 20060101
G01N023/225; H01J 37/08 20060101 H01J037/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 20, 2007 |
JP |
2007-188986 |
Claims
1. A charged particle beam apparatus, comprising: a sample stage on
which a sample is placed; a vacuum chamber to contain said sample
stage; an ion beam system to generate and focus ion beams and scan
said sample with said ion beams; a secondary particle detector to
detect secondary particles generated from said sample; and a
display device to display a secondary particle image formed by said
secondary particles; and a control device to control the charged
particle beam apparatus, wherein said charged particle beam
apparatus: sets a strip-shaped ion beam fabrication area in the
region containing said cross section from the direction of said ion
beams in a cross section nearly parallel with the direction of said
ion beams; processes said fabrication area by said ion beams;
expands said secondary particle image during processing at least in
the direction of the short side of the strip-shaped area; and
displays said secondary particle image so as to be able to judge a
cross-sectional structure by the display device.
2. The charged particle beam apparatus according to claim 1,
wherein said strip-shaped fabrication area the short side of which
is expanded is used for judging the end of the processing by said
ion beams.
3. The charged particle beam apparatus according to claim 1,
wherein, in the processing of at least one cross section,
three-dimensional data of said sample are constructed by:
processing and observing said sample continuously or
intermittently; storing observed secondary particle images in
chronological order; and using the stored secondary particle
images.
4. The charged particle beam apparatus according to claim 1,
wherein said sample is processed into a thin film and both the
surfaces of said thin film are contained in said two or more cross
sections.
5. A three-dimensional sample analysis system wherein
three-dimensional data of a sample is constructed by using at least
one of: said secondary particle images stored in chronological
order with the charged particle beam apparatus according to claim
3; secondary particle images formed by transferring said processed
sample to another charged particle beam apparatus and observed and
stored; transmitted particle images; and reflected particle
images.
6. A charged particle beam apparatus, comprising: a sample stage on
which a sample is placed; a vacuum chamber to contain said sample
stage; an ion beam system to generate and focus ion beams and scan
said sample with said ion beams; an electron beam system to
generate and focus electron beams and scan said sample with said
electron beams; a secondary particle detector to detect secondary
particles generated from said sample; a display device to display a
secondary particle image formed by said secondary particles; and a
control device to control the charged particle beam apparatus,
wherein said charged particle beam apparatus: sets a strip-shaped
ion beam fabrication area in the region containing said cross
section from the direction of said ion beams in a cross section
nearly parallel with the direction of said ion beams; processes
said fabrication area by said ion beams; expands said secondary
particle image during processing at least in the direction of the
short side of the strip-shaped area; and displays said secondary
particle image so as to be able to judge a cross-sectional
structure by the display device.
7. The charged particle beam apparatus according to claim 6,
wherein, in a sample processed into a thin film, a secondary
particle image of a cross section on one side is obtained by said
electron beams and a secondary particle image of a cross section on
the other side is obtained by said ion beams.
8. The charged particle beam apparatus according to claim 7,
wherein said secondary particle image obtained by said ion beams
and/or said secondary particle image obtained by said electron
beams are used for judging the end of the processing by said ion
beams.
9. The charged particle beam apparatus according to claim 6,
wherein, in the processing of at least one cross section,
three-dimensional data of said sample is constructed by: processing
and observing said sample continuously or intermittently; storing
secondary particle images obtained by said ion beams and/or
secondary particle images obtained by said electron beams in
chronological order; and using the stored secondary particle
images.
10. The charged particle beam apparatus according to claim 6,
Wherein said charged particle beam apparatus comprises a
transmission electron detector to detect transmitted electrons
and/or a reflected electron detector to detect reflected electrons,
and three-dimensional data of said sample is constructed by:
processing and observing said sample continuously or
intermittently; storing secondary particle images obtained by said
ion beams, secondary particle images obtained by said electron
beams, transmitted electron images obtained by said electron beams,
and/or reflected electron images obtained by electron beams in
chronological order; and using the stored images.
11. The charged particle beam apparatus according to claim 6,
wherein a secondary particle image is obtained by ion beams in an
intended region of said cross section and, after said ion beams
reach said intended region, a secondary particle image is obtained
by said electron beams.
12. A three-dimensional sample analysis system, wherein
three-dimensional data is constructed by using: said images stored
in chronological order with the charged particle beam apparatus
according to claim 9; secondary particle images formed by
transferring said processed sample to another charged particle beam
apparatus and observed and stored; transmitted particle images;
and/or reflected particle images.
13. A three-dimensional sample analysis system, wherein
three-dimensional data is constructed by using: said images stored
in chronological order with a charged particle beam apparatus
according to claim 10; secondary particle images formed by
transferring said processed sample to another charged particle beam
apparatus and observed and stored; transmitted particle images;
and/or reflected particle images.
14. The charged particle beam apparatus according to claim 1,
wherein said display device clearly specifies the cross section
from which a secondary particle image is obtained.
15. The charged particle beam apparatus according to claim 14,
wherein said display device displays at least one secondary
particle image of said cross section, and all the second particle
images in the same vertical and horizontal directions.
16. The charged particle beam apparatus according to claim 14,
wherein said display device displays at least one secondary
particle image of said cross section, and all the second particle
images in different vertical and horizontal directions.
17. The charged particle beam apparatus according to claim 4,
wherein the thickness of a thin film portion in said thin film
sample is measured and the measured thickness of said thin film
portion is used for judging the processing end.
18. A processing and observation method for displaying a
cross-sectional structure so as to be judged by: placing a sample
on a sample stage disposed in a vacuum chamber; processing said
sample by ion beams; forming at least two samples from a cross
section nearly parallel with the direction of said ion beams;
setting a strip-shaped fabrication area in the region containing
said cross section from the direction of said ion beams in a cross
section nearly parallel with the direction of said ion beams;
processing said fabrication area by said ion beams; and expanding a
secondary particle image during processing at least in the
direction of the short side of the strip-shaped area.
Description
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese patent
application serial No. 2007-188986 filed on Jul. 20, 2007, the
content of which is hereby incorporated by reference into this
application
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a technology of processing
and observing a sample by charged particle beams, and for example
to a charged particle beam apparatus to produce a processed surface
on a fine sample extracted from a substrate of a semiconductor
device by applying microprocessing to a specific portion by FIBs
(Focused Ion Beam) and observe the processed surface with a
scanning transmission electron microscope (STEM), a transmission
electron microscope (TEM), a scanning electron microscope (SEM), or
the like.
[0004] 2. Description of the Related Art
[0005] A technology on the combination of an FIB apparatus and an
STEM apparatus is disclosed in Japanese Patent Laid-Open No.
2004-228076. It shows that an STEM observation sample produced by
FIB processing is placed at the intersection of an ion beam axis
and an electron beam axis and can be subjected to additional FIB
processing and STEM observation. The ion beam axis and the electron
beam axis intersect at acute angles (about 45 degrees in the case
shown FIG. 5) and the STEM sample is rotated around a rotation
shaft perpendicular to both the axes during the time between the
additional FIB processing and the STEM observation.
[0006] Further, Japanese Patent Laid-open No. 2006-127850 describes
a technology of realizing: the omission and minimization of the
sample rotation or the like during the time between the FIB
processing and the STEM observation; and the simplification in the
operation of optimizing a sample thickness with an STEM image
monitor during processing. According to the technology, an ion beam
system, an electron beam system, and a transmitted and scattered
beam detection device are disposed around a sample, the
illumination axis of the FIB system and the illumination axis of
the electron beam system for STEM observation are arranged so as to
form nearly right angles to each other, and the sample is placed at
the intersection. By so doing, it is possible to carry out both the
FIB processing and the STEM observation without the sample
displaced.
[0007] THE TRC NEWS No. 84, July, 2003 (Kato and Otsuka, Toray
Research Center, Inc.) describes a means of three-dimensional
structural analysis by FIB processing and SEM observation. Both the
illumination axes of the FIB system and the electron beam system
intersect with each other at acute angles and it is possible to
display an image in the same region with the scanned images of both
the beams, namely with the scanning ion microscopic image (the SIM
image) and the SEM image. As it is anticipated from the electron
beam system, by processing a cross section by FIBs, it is possible
to observe the processed cross section with an SEM without the
sample inclined. By repeating the FIB processing and the SEM
observation, it is possible to integrate continuous segmented
images in the direction of the depth from the processed
surface.
[0008] The FIB processing and the STEM observation have heretofore
been carried out with separate apparatuses in many cases. A thin
film sample for an STEM processed with an FIB apparatus had to be
once extracted from the FIB apparatus, and thereafter observed with
an STEM apparatus. Thin film processing wherein an observed portion
was identified by repeating the STEM observation and the additional
FIB processing could not meet users' needs sufficiently from the
viewpoint of throughput. To cope with the problem, an apparatus
integrating FIB processing and STEM observation is announced and
the improvement of throughput is attempted.
[0009] However, in such a case as to process a sample the exact
defective portion and the defect size of which are not known into a
thin film while an intended defective portion is retained, drastic
improvement in throughput has not been attained yet because of the
reasons: (1) a thin film sample larger than an ordinary sample is
produced; (2) the repetition of FIB processing and SEM or STEM
observation by cross section monitoring is carried out more
frequently than usual and thin film processing is carried out while
the observation portion is judged; (3) the region of processing
itself expands; and others.
[0010] The fact that a cross section cannot be observed with an SEM
or an STEM during FIB processing is one of the factors that cause
throughput to be prevented from improving. Further, in the case of
a sample having plural cross sections such as a thin film sample,
when the plural cross sections are observed with an SEM or an STEM,
displacement operation such as rotation and inclination of the
sample or a sample stage is necessary in order to irradiate the
cross section to be observed with electron beams. Furthermore, once
a sample is displaced, visual field readjustment and focus
readjustment are required. From those factors, even an apparatus
integrating FIB processing and STEM observation can hardly secure a
sufficient throughput.
[0011] In the case of three-dimensional structural analysis by FIB
processing and SEM observation too, there are similar problems
since the FIB processing and the SEM observation are repeated
alternately. When the three-dimensional structural analysis is
applied to a large region, visual field deviation and focus
deviation appear in an SEM observed cross-sectional image as the
FIB processing advances, hence it is necessary to adjust the visual
field and the focus of the SEM frequently, and such operation is a
factor causing the throughput to deteriorate.
[0012] Further in recent years, in order to realize a
microstructure having high electrical characteristics, a material
called a Low-K material that is very susceptible to electron beam
irradiation has come to be used much and the cases of destroying or
deforming a sample by electron beam irradiation during SEM
observation and the like have come to happen frequently. The Low-K
material is a low permittivity materials made of, for example,
organic polymer or SiOC etc. As measures against the cases, means
such as (1) to mitigate damage by cooling a sample, (2) to
extremely lower the acceleration voltage of electron beams and
reduce irradiation energy, and others have been taken.
[0013] However, the means (1) requires time for cooling and
exchanging samples and the throughput of processing lowers
enormously. Further, the damage caused by electron beam irradiation
appears locally and the observed portion deforms even though the
sample stage is cooled unless a cooling path is sufficiently
secured. A drawback of the means (2) is that the image resolution
of an SEM lowers by lowering the acceleration voltage of electron
beams and the microstructure is hardly recognized.
SUMMARY OF THE INVENTION
[0014] An object of the present invention is to process a sample by
charged particle beams and monitor the processed cross section with
a high throughput.
[0015] The present invention relates to observing a cross-sectional
structure during FIB processing as a secondary particle image
generated from a sample by using ion beams shaving the cross
section.
[0016] The present invention makes it possible to observe a cross
section by ion beams used for processing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1A and 1B are general configuration diagrams of a
charged particle beam apparatus having an ion beam system;
[0018] FIGS. 2A and 2B are general configuration diagrams of a
charged particle beam apparatus having an ion beam system and an
electron beam system;
[0019] FIGS. 3A and 3B show an embodiment of three-dimensional data
construction;
[0020] FIG. 4 shows an embodiment of three-dimensional data
construction;
[0021] FIG. 5 shows an embodiment of three-dimensional data
construction;
[0022] FIGS. 6A and 6B show a general configuration diagram of a
charged particle beam apparatus having an ion beam system and an
electron beam system and an embodiment of three-dimensional data
construction;
[0023] FIG. 7 shows an embodiment of three-dimensional data
construction;
[0024] FIG. 8 shows an embodiment of three-dimensional data
construction;
[0025] FIG. 9 shows an embodiment of cross-sectional image
display;
[0026] FIGS. 10A and 10B show an embodiment of cross-sectional
image display;
[0027] FIGS. 11A and 11B show an embodiment of cross-sectional
image display;
[0028] FIG. 12 shows an embodiment of thin film thickness
measurement;
[0029] FIG. 13 shows an embodiment of three-dimensional data
construction;
[0030] FIG. 14 shows an embodiment of three-dimensional data
construction; and
[0031] FIG. 15 shows an embodiment of cross-sectional image
display.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] The present inventors have earnestly studied and obtained
the following knowledge.
[0033] In order to produce an accurate sample while an intended
defective region is retained even though the location and size of
the defect in the sample is unknown, it is necessary to produce at
least two cross sections and advance the processing of the sample
while the processing and the monitoring of the processed
cross-sections are carried out. A high throughput in processing and
monitoring of a processed cross section may be obtained by:
observing a cross-sectional structure during FIB processing as a
secondary particle image generated from a sample by using ion beams
shaving the cross section; and thereby making it possible to carry
out both the processing and the observation at the same time. By so
doing, it is possible to obtain a high throughput also in the
process of repeating the processing and the monitoring of the
processed cross sections and analyzing the structure of the
sample.
[0034] At the final stage of shaving a cross section, a fabrication
area forms a shape of a strip and usually an observed image also
has a strip shape. The end point of the processing has heretofore
been judged by the average brightness of a whole observed image.
Consequently, although the process of advancing cross-sectional
processing from the surface toward the sample substrate has roughly
been obtained, the structure of the cross section has hardly been
obtained. To cope with the problem, the combined use of an SEM has
been studied. In the present invention, the observation is arranged
so as to be displayed expansively in the direction of the short
side of the strip shape and the cross-sectional structure is
arranged so as to be obtained only by FIBs during processing.
[0035] In general, a processed cross section is formed by FIB
processing so as to incline at an angle of several degrees to the
incident angle of ion beams in consideration of the relationship
between a local angle of the ion beams incoming to a sample and a
sputtering efficiency (J. Vac. Sci. Technol. B9(5),
September/October 1991, pp 2636). In the present invention, a
cross-sectional structure can be displayed by: using the physical
phenomenon; setting a strip-shaped fabrication area at an inclined
portion; and displaying the processing monitor expansively in the
short side direction. Although the image resolution deteriorates
worse than the beam diameter since the beams are applied from a
direction oblique to, nearly parallel with, the cross section, it
is possible to display an image that is sufficient in obtaining a
cross-sectional structure such as the existence of a wiring
structure. The cross-sectional structure is observed by using the
function and, when an intended cross section is not attained yet,
the fabrication area shifts in the direction of the cross section
and the processing and the judgment of the cross-sectional
structure are repeated. By so doing, it is possible to attain an
intended cross section without the combined use of an SEM.
[0036] A region requiring high resolution observation with an SEM,
an STEM, or a TEM is only a part of a sample and hence the other
region not requiring high resolution observation is subjected to
the aforementioned FIB processing observation and, when another
region requiring high resolution observation appears, the FIB
processing observation is switched to SEM, STEM, or TEM
observation. By so doing, it is possible to reduce stage shift and
switching operation between FIB processing and SEM, STEM, or TEM
observation.
[0037] Even in the case of using three-dimensional structural
analysis by FIB processing and SEM observation and a material that
is very susceptible to electron beam irradiation, a region
requiring high resolution observation with an SEM, an STEM, or a
TEM is only a part of a sample. Consequently, the other region not
requiring high resolution observation is subjected to the
aforementioned FIB processing observation and, when another region
requiring high resolution observation appears, the FIB processing
observation is switched to SEM, STEM, or TEM observation. By so
doing, it is possible to: reduce the visual field readjustment and
the focus readjustment of an SEM observed cross-sectional image
that is required as the FIB processing advances; and also reduce
the amount of electron beams applied to a material that is very
susceptible to electron beam irradiation.
[0038] In the present invention, it is possible to produce an
accurate sample with a high throughput while an intended region is
retained even though the exact defective portion of the sample is
not known in the process for producing the sample such as a thin
film while processing and monitoring of a processed cross section
are repeated. Further, in the process for repeating processing and
monitoring of a processed cross section and applying
three-dimensional structural analysis to a sample too, the
throughput of the analysis can be improved. Moreover, it is
possible to observe a cross section infinitely close to a true
appearance even with a material that is very susceptible to
electron beam irradiation.
[0039] Since the processing and observation of a cross section can
be simultaneously carried out by ion beams used for the processing,
it is possible to reduce: stage transfer for monitoring the cross
section during processing; SEM visual field adjustment; and SEM
focus adjustment. Further, since the processing and observation are
carried out by ion beams incoming perpendicularly to the sample
surface, the location where a cross section is formed is not
restricted. Consequently, however an intended region is placed,
vertically, transversely, or obliquely, as long as at least two
cross sections are formed and processing and monitoring are
repeated, it is possible to retain the intended region without
fail. Also when plural processed cross sections are monitored, it
is not necessary to move a stage in order to monitor a cross
section except the case of high-resolution observation using an
SEM, an STEM, or a TEM. In addition, it is not necessary to
readjust the focus of ion beams since the position of a sample is
not changed. In the present invention, unnecessary stage transfer,
accompanying beam adjustment, SEM, STEM, or TEM observation for
cross section monitoring can be avoided and hence it is possible to
carry out with a high throughput the process accompanying
continuous or intermittent processing and the monitoring of a
processed cross section, for example aforementioned production of a
thin film sample and three-dimensional structural analysis.
Further, information on a cross section that has not been obtained
during FIB processing can be obtained and the information on a
cross section can be obtained not only as discrete data but also as
continuous motion picture data.
[0040] Further, since an intended cross section can be formed
without the combined use of an SEM, it is possible to carry out FIB
cross section processing and thin film processing while damage and
deformation in a cross section of a sample susceptible to electron
beam irradiation are inhibited. A cross section to which the FIB
processing is applied in a vacuum is clean and has no impurities
such as an adsorption gas and hence, by installing an FIB, an SEM,
an STEM, or the like in an identical vacuum chamber, it is possible
to observe at a high resolution an unlimitedly clean surface
having: extremely small damage and deformation in the sample
susceptible to electron beam irradiation; and scarce adsorption
gas.
Embodiment 1
[0041] FIG. 1A is a general configuration diagram of a charged
particle beam apparatus and FIG. 1B is a general configuration
diagram on the display of a secondary particle image formed by ion
beams during processing. In the present embodiment, the charged
particle beam apparatus shown in FIGS. 1A and 1B comprises: an ion
beam system 1 to generate and focus ion beams 11 and scan a sample
3 with the ion beams 11; a secondary particle detector 5 to detect
secondary particles generated from the sample 3; a sample stage 4
on which the sample 3 is placed; a vacuum chamber 8 in which the
sample stage 4 is placed; a display device 6 to display a secondary
particle image 15 formed by the secondary particles; and a control
device 7 to control constituent components. The control device 7
has the function of carrying out the following processes:
(1) to form cross sections (A) 9 and (B) 10 in nearly parallel with
the beam irradiation direction 12 by the irradiation of ion beams
11; (2) to set a strip-shaped fabrication area 13 at the region
where the cross sections are contained and process the region from
the beam irradiation direction 12; and (3) to display the secondary
particle image 15 during processing at least so as to expand the
strip shape in the direction of the short side.
[0042] On the display device 6, as a shown in FIG. 1B, a secondary
particle image 13 is expanded in the process (3) and displayed as
an image 14. At least two cross sections (A) 9 and (B) 10 or more
are formed in the sample 3 and the processes (1), (2), and (3) are
used at least once or more for the observation of the cross
sections (A) 9 and (B) 10.
[0043] Since a cross section formed by FIB processing has an angle
18 of about 3 to 6 degrees from the beam irradiation direction 12,
the cross section in the scanning area 19 of the ion beams can be
observed as a secondary particle image 15 during processing even by
the ion beams 11 incoming perpendicularly to the sample surface.
The outline of a cross-sectional structure is obtained by
displaying the strip-shaped secondary particle image in an expanded
manner and it is possible to judge the cross-sectional structure by
the ion beams incoming perpendicularly to the sample surface
without a stage inclined. By so doing, it is possible to reduce or
omit: the operation of interrupting processing in order to observe
a cross section, switching the ion beams 11 from the ion beams for
processing to ion beams for observation, and displacing (in X, Y,
and Z directions, rotation, inclination, etc.) a sample stage 4 to
a location where the cross section can be observed; the operation
of interrupting processing and displacing the sample 3 to another
apparatus such as an SEM or an STEM; or both the operations.
Further, in the present invention, since the cross-sectional
structure is observed at the same time with processing, switching
from processing to observation is unnecessary. By those effects, it
is possible to considerably improve the operation efficiency of
processing and observation requiring accurate judgment of
processing end in order to surely retain an intended defective
portion while the defective portion is searched particularly in a
sample the accurate defective portion of which is unknown. Although
the case of processing and observing two cross sections is shown in
the present embodiment, the number of the cross sections is not
particularly limited and the orientations of the cross sections can
be set arbitrarily. Further, a cross section is not necessarily
planar but may be round. In a conventional case, since processing
and observation are carried out alternately, the observation data
of a cross section come to be discrete data such as images or the
like. In the present embodiment, since processing and observation
are carried out simultaneously, it is possible to obtain the
observation data of a cross section not only as discrete data such
as images but also as continuous data such as motion picture
data.
[0044] FIGS. 3A and 3B show an embodiment of three-dimensional data
construction of the sample 3 according to the present embodiment 1.
FIG. 3A shows an embodiment of three-dimensional data construction
in a fabrication area of thin film processing and FIG. 3B shows an
embodiment of three-dimensional data construction in a fabrication
area of a bulk sample. The present embodiment shows
three-dimensional data construction using discrete image data.
Processing and observation are carried out continuously or
intermittently and secondary particle images 14 expansively showing
the cross section (A) 9 are obtained one by one and stored in
relation to the positional information of the cross sections. The
plural pieces of stored image data are aligned in the processing
direction 31 of the cross sections, the linkage between adjacent
images is complemented, and thereby the three-dimensional data (A)
32 of the sample 3 is constructed. Although the three-dimensional
data is constructed in one fabrication area in the present
embodiment, the number of the fabrication area may be plural.
Further, not only images but also mapping data for elemental
analysis may be accepted. It is also possible to construct seamless
three-dimensional data (A) 32 of the sample 3 by using motion
picture data. The constructed three-dimensional data (A) 32 may be
corrected so that the dimensional ratio of length to width may
conform to actual dimensional ratio of the sample 3.
[0045] FIG. 4 shows another embodiment of three-dimensional data
construction of the sample 3 in the embodiment 1. Processing and
observation are carried out continuously or intermittently with a
charged particle beam apparatus 101 according to the present
invention and secondary particle images 14 expansively showing the
cross section (A) 9 and the cross section (B) 10 are obtained one
by one and stored in relation to the positional information of the
cross sections. The sample 3 is subjected to thin film processing
until a film thickness through which electron beams 103 pass is
obtained. Successively, the processed sample 100 is transferred to
another electron beam apparatus 102 and a transmitted particle
image 22 of the processed sample 100 is obtained. The data is also
stored in relation to the positional information in the sample
3.
[0046] The plural pieces of image data obtained and stored with the
charged particle beam apparatus 101 are corrected so that the
dimensional ratio of length to width may conform to the actual
dimensional ratio of the sample 3 and aligned in the processing
direction 31 of the cross sections. Then image data obtained and
stored with another electron beam apparatus 102 is added to the
data group, the linkage between adjacent images is complemented,
and thereby the three-dimensional data (B) 33 of the sample 3 are
constructed. In the case of the present embodiment, the data is
produced by synthesizing a scanning ion microscopic image (an SIM
image) formed by ion beams 11 and a transmission electron
microscopic image (a TEM image). The data obtained with another
electron beam apparatus 102 may be a secondary electron image or a
reflected electron (backscattered electron) image. The data
obtained with the charged particle beam apparatus 101 may be motion
picture data.
Embodiment 2
[0047] FIGS. 2A and 2B show an embodiment of a charged particle
beam apparatus having an ion beam system and an electron beam
system. FIG. 2A is a general configuration diagram of a charged
particle beam apparatus and FIG. 2B is, same as FIG. 1B, a general
view explaining the display of a secondary particle image formed by
ion beams during processing. The present embodiment is a composite
device formed by adding an electron beam system 2 to generate
electron beams 16, focus them, and scan a sample with them to the
embodiment shown in FIGS. 1A and 1B. The ion beam system 1 and the
electron beam system 2 are disposed so that the beam irradiation
direction 12 of the ion beams 11 may intersect with the electron
beam irradiation direction 17 of the electron beams 16 at a certain
point. A sample 3 is placed in the vicinity of the point where the
beam irradiation direction 12 of the ion beams 11 intersects with
the electron beam irradiation direction 17 of the electron beams
16. Either of the cross section (A) 9 or the cross section (B) 10,
the cross section (B) 10 in the present embodiment, is formed at
the position that can be irradiated with the electron beams 16. In
the present embodiment, in addition to the effects in the
embodiment 1 shown in FIGS. 1A and 1B, it is possible to: observe
the cross section (B) 10 at a high-resolution by using the electron
beam system 2; and obtain a more detailed cross-sectional
structure. When high resolution observation with the electron beam
system 2 is used for judging the end of processing, it is possible
to judge the end of processing with a higher degree of
accuracy.
[0048] FIG. 5 shows an embodiment of three-dimensional data
construction of the sample 3 used in the embodiment 2 shown in
FIGS. 2A and 2B. The present embodiment shows three-dimensional
data construction formed by using discrete image data. Processing
and observation are carried out continuously or intermittently and
secondary particle images 14 expansively showing the cross section
(A) 9 are obtained one by one and stored in relation to the
positional information of the cross sections. In the case of the
cross section (B) 10, secondary particle images 41 are obtained one
by one by electron beams 16 and stored in relation to the
positional information of the cross sections. The stored plural
pieces of image data are corrected so that the dimensional ratio of
length to width may conform to the actual dimensional ratio of the
sample 3 and aligned in the processing direction 31 of the cross
sections, the linkage between adjacent images is complemented, and
thereby the three-dimensional data (A) 32 of the sample 3 is
constructed. Although the three-dimensional data is constructed in
two fabrication areas in the present embodiment, the number of the
fabrication areas may be two or more. Further, not only images but
also mapping data for elemental analysis may be accepted. In the
case of the cross section (A) 9, it is also possible to construct
seamless three-dimensional data of the sample 3 by using motion
picture data. In the case of the cross section (B) 10, the data
obtained by electron beams 16 and the data obtained by ion beams 11
may be mixed to form mixed data. Although the explanations are made
on the basis of the case of processing a sample into a convex shape
in the present embodiment, it is also possible to construct
three-dimensional data (A) 32 by forming a thin film portion in a
bulk sample as shown in FIG. 7.
Embodiment 3
[0049] FIGS. 6A and 6B show another embodiment of a charged
particle beam apparatus having an ion beam system and an electron
beam system. FIG. 6A is a general configuration diagram of a
charged particle beam apparatus and FIG. 6B is a general view
explaining the three-dimensional data construction of the sample 3.
The present embodiment is a composite device formed by adding a
transmission electron detector 42 to detect transmitted electrons
and a reflected electron detector 43 to detect reflected electrons
(backscattered electrons) to the embodiment 2 shown in FIGS. 2A and
2B. In the observation of thin film cross sections of the sample 3,
the cross section (B) 10 facing electron beams 16 is observed by a
secondary electron image 41 formed by electron beams and the end of
processing is judged and the cross section (A) 9 is observed by an
expansively displayed secondary electron image 14 and the end of
the processing is judged. Then the thin film is processed to an
intended region without the movement of a stage. A transmission
electron image 44 is obtained from the produced thin film sample
with the transmission electron detector 42 and observed at a high
resolution. It is possible to obtain a reflected electron
(backscattered electron) image by detecting not only transmitted
electrons but reflected electrons (backscattered electrons).
Further, it is possible to construct three-dimensional data (A) 32
similar to that of the embodiment shown in FIG. 5. The
aforementioned processing and observation can be carried out in a
charged particle beam apparatus and hence the sample 3 is never
exposed to the air and it is possible to observe or analyze a clean
surface having no adsorbed gas. By installing a heater in the
vacuum chamber 8, it is possible to further reduce the gas adsorbed
on the surface and observe and analyze a cleaner surface.
[0050] FIG. 8 shows an embodiment wherein the three-dimensional
data described in FIG. 4 is constructed with a charged particle
beam apparatus having an ion beam system 1 and an electron beam
system 2 shown in FIGS. 2A and 2B or 6. With the charged particle
beam apparatus 101 according to the present invention too, a sample
can be observed at a high resolution by electron beams 16. In the
charged particle beam apparatus 101, a sample is observed at an
acceleration voltage of 30 kV with an STEM, successively the
processed sample 100 is transferred to another electron beam
apparatus 102, and the sample is observed at a higher resolution at
an acceleration voltage of 200 kV with the STEM. The
three-dimensional data (B) 33 is constructed with the data.
[Display Device]
[0051] FIG. 9 is an embodiment showing how to specify the cross
sectional image of the sample 3 corresponding to the secondary
particle image 14 expansively displayed on the display device 6. On
the display device 6, the secondary particle image 14 is
expansively displayed together with the set processing pattern (A)
51 and processing pattern (B) 52. An operator is informed of which
processing pattern is processed and observed as the expansively
displayed secondary particle image 14 by indicating the
corresponding processing pattern with the arrow 53.
[0052] FIGS. 10 and 11 are other embodiments showing which
cross-sectional image of the sample 3 corresponds to the secondary
particle image 14 expansively displayed on the display device 6. In
the embodiment of FIGS. 10A and 10B, the corresponding processing
pattern is indicated with the arrow 53 and the display manner of
the secondary particle image expansively displayed is changed for
each set processing pattern. In the embodiment, an operator is
informed of the cross-sectional image now processed and observed by
displaying the expansively displayed secondary particle image (A)
54 and the expansively displayed secondary particle image (C) 56
inversely in the vertical direction. Meanwhile, the embodiment
shown in FIGS. 11A and 11B is the opposite of that shown in FIGS.
10A and 10B. That is, all the expansively displayed cross-sectional
images are displayed in the same direction so that an operator may
judge the cross-sectional images. In the present embodiment, the
expansively displayed secondary particle image (A) 54 and the
expansively displayed secondary particle image (B) 55 are displayed
in the same direction and an operator is informed of the currently
processed and observed cross section by indicating the
corresponding processing pattern with the arrow 53 in the same way
as the embodiment shown in FIG. 9. Here, in the embodiment, the
case of two cross sections is shown but the number of cross
sections is not limited.
[0053] FIG. 12 shows an embodiment of monitoring and measuring the
thickness of the thin film portion 60 in the sample 3. A secondary
particle image 15 wherein the thickness of the thin film portion is
observed is displayed on the display device 6, the thickness of the
thin film portion 60 is automatically measured when two long side
cursors of the thin film portion 60, a cursor (A) 61 and a cursor
(B) 62, are adjusted and the measured value is displayed on the
thickness display unit 63 in the display device 6. It is possible
to judge the processing end more accurately by using the
information on the thickness of the thin film portion 60 for the
judgment of the processing end.
[0054] FIG. 13 shows an embodiment of constructing
three-dimensional data of a prismatic micro-column with a charged
particle beam apparatus 101 and another electron beam apparatus 102
according to the present invention. The structural analysis of a
prismatic micro-column 108 has heretofore been done by: removing a
fabrication area (A) 111, a fabrication area (B) 112, a fabrication
area (C) 113, and a fabrication area (D) 114 from a bulk sample 3
by ion beams 11; forming the prismatic micro-column 108 as a fine
columnar sample; thereafter transferring the prismatic micro-column
108 to an STEM or a TEM; and observing transmitted particle images
22 at a high resolution from various directions. On this occasion,
in order to prevent throughput from lowering, information on the
fabrication area (A) 111, the fabrication area (B) 112, the
fabrication area (C) 113, and the fabrication area (D) 114 is
rejected. That is, such an operation as to interrupt the processing
and observe the cross sections during the processing of the
fabrication area (A) 111, the fabrication area (B) 112, the
fabrication area (C) 113, and the fabrication area (D) 114 is not
carried out. In the present embodiment, since a cross section can
be observed simultaneously during processing by the charged
particle beam apparatus, it is possible to obtain the
cross-sectional information of the fabrication area (A) 111, the
fabrication area (B) 112, the fabrication area (C) 113, and the
fabrication area (D) 114 while the throughput is not lowered. The
cross-sectional information corresponding to the four fabrication
areas is stored as the three-dimensional data (A) 32, in relation
to the positional information showing the locations of the cross
sections in the sample 3 and the three-dimensional data (B) 33 of
the sample 3 is constructed by combining the stored information
with the information on the structure of the prismatic micro-column
108 observed with another electron beam apparatus 102, on this
occasion an STEM or a TEM. The information used for the
construction of the three-dimensional data (B) 33 is not
necessarily a cross-sectional image of the same size as described
in FIGS. 4 and 8.
[0055] FIG. 14 shows an embodiment of the three-dimensional data
construction of a micro-cylinder. A micro-cylinder 109 as a fine
columnar sample is produced by: rotating a sample stage 4 in the
sample rotation direction 123 while a sample is scanned with ion
beams 11 in the scanning direction 121; and gradually moving the
ion beams 11 toward the shift direction 122. In the present
embodiment, the number of the cross-sectional image is one because
the sample 3 is rotated and processed into a columnar shape. The
display device 6 displays an expansively displayed secondary
particle image 14 so as to be viewed panoramically from the
rotation axis of the sample. It is possible to construct the
three-dimensional data (B) 33 of the sample 3 by combining the data
in the radius direction. It is also possible to construct such a
three-dimensional data as described in FIG. 13 by transferring a
micro-column 109 to another electron beam apparatus and subjecting
it to structural analysis.
[0056] FIG. 15 shows an embodiment of displaying an expansively
displayed secondary particle image when four cross sections are
processed and observed. The sample 3 is irradiated from above with
ion beams 11 and the four cross sections (C) 131, (D) 132, (E) 133,
and (F) 134 are processed and observed. The upper surface image and
the cross-sectional images (C) 141, (D) 142, (E) 143, and (F) 144
on the four sides of the sample 3 are displayed on the display
device 6 like a development view in place of displaying each
cross-sectional image individually on the display device 6 as shown
in FIGS. 9, 10, and 11. The processing end is judged while the
upper surface image and the four cross-sectional images of the
sample 3 are observed.
[0057] In the present embodiments, it is possible to produce an
accurate sample with a high throughput without an intended region
lost in the process for producing a sample such as a thin film
while processing and monitoring of a processed cross section are
repeated even with a sample the accurate defective position of
which is not known. Further, it is possible to improve analysis
throughput in a process of repeating processing and monitoring of a
processed cross section and analyzing the three-dimensional
structure of the sample. Furthermore, it is possible to observe a
cross section extremely close to the true feature even with a
material very susceptible to electron beam irradiation.
* * * * *