U.S. patent application number 16/357796 was filed with the patent office on 2020-09-24 for holder and charged particle beam apparatus.
The applicant listed for this patent is HITACHI HIGH-TECHNOLOGIES CORPORATION. Invention is credited to Kotaro HOSOYA.
Application Number | 20200303157 16/357796 |
Document ID | / |
Family ID | 1000005074023 |
Filed Date | 2020-09-24 |
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United States Patent
Application |
20200303157 |
Kind Code |
A1 |
HOSOYA; Kotaro |
September 24, 2020 |
HOLDER AND CHARGED PARTICLE BEAM APPARATUS
Abstract
According to one embodiment, a holder includes a top member, a
side member, and a bottom member. The top member has a hole for
allowing transmission of a charged particle beam, and the sample is
mountable in the hole. The bottom member is provided to overlap
with the top member in a plan view. The side member is connected to
a part of the top member and a part of the bottom member such that
the top member and the bottom member are separated from each other
in a cross-sectional view. An opening portion is a region
surrounded by the top member, the side member, and the bottom
member, and a scintillator is provided in the opening portion.
Inventors: |
HOSOYA; Kotaro; (Agoura
Hills, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI HIGH-TECHNOLOGIES CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
1000005074023 |
Appl. No.: |
16/357796 |
Filed: |
March 19, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01J 37/244 20130101;
H01J 37/26 20130101; H01J 37/226 20130101; H01J 37/20 20130101;
H01J 37/224 20130101 |
International
Class: |
H01J 37/20 20060101
H01J037/20; H01J 37/244 20060101 H01J037/244; H01J 37/22 20060101
H01J037/22 |
Claims
1. A holder comprising: a top member that has a first hole for
allowing transmission of a charged particle beam and in which a
sample is mountable in the first hole; a bottom member that is
provided to overlap with the top member in a plan view; a side
member that is connected to a part of the top member and a part of
the bottom member such that the top member and the bottom member
are separated from each other in a cross-sectional view; an opening
portion that is a region surrounded by the top member, the side
member, and the bottom member; a first scintillator that is
provided in the opening portion; and a first optical member
including a first light guide that has a function of allowing
transmission of light and not allowing transmission of an X-ray,
and a second hole that is provided in the first light guide,
wherein the first optical member is provided in the opening portion
such that a part of a side surface of the first light guide is
exposed from the side member, the second hole overlaps with the
first hole in a plan view, and the first scintillator is provided
between the first light guide and the bottom member such that a
part of the first scintillator is exposed in the second hole.
2. (canceled)
3. The holder according to claim 1, further comprising: a second
optical member including a second light guide and a third light
guide each of which has a function of allowing transmission of
light and not allowing transmission of an X-ray, a blocking layer
that is provided between the second light guide and the third light
guide and has a function of not allowing transmission of light and
an X-ray, a third hole that is provided in the second light guide,
and a fourth hole that is provided in the second light guide, in
the blocking layer, and in the third light guide, communicates with
the third hole, and has a narrower aperture than the third hole,
wherein the second optical member is provided in the opening
portion such that a part of a side surface of each of the second
light guide and the third light guide is exposed from the side
member, each of the third hole and the fourth hole overlaps with
the first hole in a plan view, the first scintillator is provided
on the second light guide positioned around the fourth hole in the
third hole, and a second scintillator is provided between the third
light guide and the bottom member such that a part of the second
scintillator is exposed in the fourth hole.
4. The holder according to claim 3, wherein the blocking layer
partially covers a side surface of each of the second light guide
and the third light guide, and the respective side surfaces of the
second light guide and the third light guide that are exposed from
the blocking layer and the side member are positioned opposite to
each other.
5. The holder according to claim 3, wherein the second optical
member has a planar shape in which a notch is provided in a part of
a circular shape or an elliptical shape, and the second optical
member is provided in the opening portion such that the notch is in
contact with the side member.
6. The holder according to claim 3, wherein each of the light that
is capable of transmitting through each of the second light guide
and the third light guide and the light that is not capable of
transmitting through the blocking layer is light from a
vacuum-ultraviolet range to a visible range, a material forming
each of the second light guide and the third light guide is glass
or an acrylic resin, and a material forming each of the blocking
layer, the top member, the side member, and the bottom member is a
metal or an alloy.
7. The holder according to claim 1, further comprising a second
optical member including a second light guide and a third light
guide each of which has a function of allowing transmission of
light and not allowing transmission of an X-ray, a blocking layer
that is provided between the second light guide and the third light
guide and has a function of not allowing transmission of light and
an X-ray, a third hole that is provided in the second light guide,
and a fourth hole that is provided in the second light guide and in
the blocking layer, communicates with the third hole, and has a
narrower aperture than the third hole, wherein the second optical
member is provided in the opening portion such that a part of a
side surface of each of the second light guide and the third light
guide is exposed from the side member, each of the third hole and
the fourth hole overlaps with the first hole in a plan view, the
first scintillator is provided on the second light guide positioned
around the fourth hole in the third hole, and a second scintillator
is provided on the third light guide such that a part of the second
scintillator is exposed in the fourth hole.
8. A charged particle beam apparatus comprising: a chamber; a
charged particle optical lens barrel that is attached to an upper
portion of the chamber and is capable of emitting a charged
particle beam; a stage that is attached to a lower portion of the
chamber; a holder that is provided on the stage; a first light
detector that is positioned above the holder to be separated from
the holder and is attached to the upper portion of the chamber,
wherein the holder includes a top member that has a first hole and
in which a sample is mountable in the first hole, a bottom member
that is provided to overlap with the top member in a plan view, a
side member that is connected to a part of the top member and a
part of the bottom member such that the top member and the bottom
member are separated from each other in a cross-sectional view, an
opening portion that is a region surrounded by the top member, the
side member, and the bottom member, and a first scintillator that
is provided in the opening portion, and a first optical member
including a first light guide that has a function of allowing
transmission of light and not allowing transmission of an X-ray,
and a second hole that is provided in the first light guide,
wherein the first optical member is provided in the opening portion
such that a part of a side surface of the first light guide is
exposed from the side member, the second hole overlaps with the
first hole in a plan view, and the first scintillator is provided
between the first light guide and the bottom member such that a
part of the first scintillator is exposed in the second hole; and
the first light detector has a function capable of detecting first
light that is emitted from the first scintillator and exits from
the opening portion when the sample is mounted on the top member,
the sample in the first hole is irradiated with the charged
particle beam emitted from the charged particle optical lens
barrel, and transmitted charged particles transmitted through the
sample collide with the first scintillator.
9. The charged particle beam apparatus according to claim 8,
further comprising: an X-ray detector that is positioned above the
holder to be separated from the holder and is attached to the upper
portion of the chamber, wherein the first light emitted from the
first scintillator transmits through the inside of the first light
guide and exits from the opening portion such that the side surface
of the first light guide is a first exit surface, the X-ray
detector has a function capable of detecting an X-ray emitted from
the sample when the sample is irradiated with the charged particle
beam, and the first light guide has a function of allowing
transmission of the first light and not allowing transmission of an
X-ray.
10. The charged particle beam apparatus according to claim 8,
wherein the holder further includes a second optical member
including a second light guide, a third light guide, a blocking
layer that is provided between the second light guide and the third
light guide such that the second light guide and the third light
guide are not in contact with each other, the first scintillator
that is in contact with the second light guide, and a second
scintillator that is in contact with the third light guide, the
second optical member is provided in the opening portion such that
a part of a side surface of each of the second light guide and the
third light guide is exposed from the side member, the transmitted
charged particles include first transmitted charged particles that
collide with the first scintillator and second transmitted charged
particles that transmit through the sample at a smaller scattering
angle than the first transmitted charged particles and collide with
the second scintillator, when the first transmitted charged
particles collide with the first scintillator, the first light is
emitted from the first scintillator, transmits through the inside
of the second light guide, and exits from the opening portion such
that the side surface of the second light guide is a second exit
surface, when the second transmitted charged particles collide with
the second scintillator, second light is emitted from the second
scintillator, transmits through the inside of the third light
guide, and exits from the opening portion such that the side
surface of the third light guide is a third exit surface, 1the
second light guide has a function of allowing transmission of the
first light and not allowing transmission of an X-ray, the third
light guide has a function of allowing transmission of the second
light and not allowing transmission of an X-ray, and the blocking
layer has a function of not allowing transmission of the first
light, the second light, and an X-ray.
11. The charged particle beam apparatus according to claim 10,
wherein the blocking layer partially covers the side surface of
each of the second light guide and the third light guide such that
the second exit surface and the third exit surface are exposed, and
the second exit surface and the third exit surface exposed from the
blocking layer and the side member are positioned opposite to each
other.
12. The charged particle beam apparatus according to claim 11,
wherein the second light is detected by the first light detector by
rotating the stage.
13. The charged particle beam apparatus according to claim 11,
further comprising: a second light detector that is positioned
above the holder to be separated from the holder and is attached to
the upper portion of the chamber, wherein the first light detector
is positioned closer to the second exit surface than the second
light detector, the second light detector is positioned closer to
the third exit surface than the first light detector, the first
light is detected by the first light detector, and the second light
is detected by the second light detector.
14. The charged particle beam apparatus according to claim 8,
wherein the first light detected by the first light detector is
attached to the inside or outside of the charged particle beam
apparatus and is converted into image data regarding a transmitted
charged particle image of the sample by an image processing
apparatus connected to the first light detector.
15. A charged particle beam apparatus comprising: a chamber; a
charged particle optical lens barrel that is attached to an upper
portion of the chamber and is capable of emitting a charged
particle beam; a stage that is attached to a lower portion of the
chamber; a holder that is provided on the stage; and a first light
detector and an X-ray detector that are positioned above the holder
to be separated from the holder and are attached to the upper
portion of the chamber, wherein the stage includes a base portion
that is attached to the lower portion of the chamber, a rotation
portion that is provided on the base portion and includes a
rotation mechanism, a rotary table that includes a plurality of
first holes and in which a plurality of samples are mountable in
the first holes, and a pillar portion that is connected to the
rotary table and the rotation portion, the holder includes a bottom
member that is provided to overlap with a part of the rotary table
in a plan view, a side member that is provided between the rotary
table and the bottom member and is connected to a part of the
bottom member, an opening portion that is a region surrounded by
the rotary table, the side member, and the bottom member, a first
scintillator that is provided in the opening portion, and a first
optical member that includes a first light guide and a second hole
provided in the first light guide and is provided in the opening
portion such that a part of a side surface of the first light guide
is exposed from the side member, the first light detector has a
function capable of detecting first light that is emitted from the
first scintillator and exits from the opening portion when the
sample is mounted on the rotary table, the sample in the first hole
is irradiated with the charged particle beam emitted from the
charged particle optical lens barrel, and transmitted charged
particles transmitted through the sample collide with the first
scintillator, the X-ray detector has a function capable of
detecting an X-ray emitted from the sample when the sample is
irradiated with the charged particle beam, the second hole overlaps
with the first hole in a plan view, the first scintillator is
provided between the first light guide and the bottom member such
that a part of the first scintillator is exposed in the second
hole, the first light emitted from the first scintillator transmits
through the inside of the first light guide and exits from the
opening portion such that the side surface of the first light guide
is a first exit surface, and the first light guide has a function
of allowing transmission of the first light and not allowing
transmission of an X-ray.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a holder and a charged
particle beam apparatus and particularly can be suitably used for
detecting light using a holder.
2. Description of Related Art
[0002] In order to scan a sample with an electron beam to obtain a
desired transmission electron image from the sample, for example, a
charged particle beam apparatus such as a scanning transmission
electron microscope (STEM) or a scanning electron microscope (SEM)
is used. In the scanning electron microscope, even at a relatively
low acceleration voltage of several tens of kV, a transmission
electron image with an extremely high contrast and a high
resolution can be obtained.
[0003] For example, FIG. 21 illustrates a charged particle beam
apparatus of the prior art. As illustrated in FIG. 21, a sample SAM
is mounted on a mesh MS provided in a holder HL in a charged
particle beam apparatus, and a reflecting plate RF is provided in a
region of the holder HL below the sample SAM. Here, a transmitted
electron EB4 having transmitted downward through the sample SAM
when the sample SAM is irradiated with a charged particle beam EB1
is reflected from the reflecting plate RF that is obliquely
inclined. Reflected secondary electrons EB5 are detected by a
detector ETD called an Everhart Thornley detector.
[0004] In addition, JP-A-2008-66057 discloses a technique in which
a transmitted electron having transmitted downward through a sample
when the sample is irradiated with an electron beam is caused to
collide with an obliquely inclined scintillator such that light
emitted from the scintillator is caused to transmit through a
through hole in a horizontal direction and is incident into a
photomultiplier tube provided in an exit of the through hole.
[0005] In addition, JP-A-2013-225530 discloses a technique in which
exciting light having image information is detected by causing a
luminescent phenomenon to occur using gas scintillation in a
chamber that is controlled to be in a low vacuum of about 1 Pa to
3000 Pa, and also discloses a detector that can detect the exciting
light.
SUMMARY OF THE INVENTION
[0006] In the prior art illustrated in FIG. 21, electrons detected
by the detector ETD include not only the secondary electrons EB5
reflected from the reflecting plate RF but also secondary electrons
EB6 emitted from a surface of the sample SAM. Accordingly, it is
difficult to generate an accurate transmission electron image based
on the secondary electrons EB5 detected by the detector ETD. In
particular, in the technique illustrated in FIG. 21, when the
sample SAM is thick, the amount of the secondary electrons EB6
increases such that the contrast of the transmission electron image
may vary largely. From this point of view, it is also difficult to
generate an accurate transmission electron image with the technique
of FIG. 21.
[0007] In addition, redundant transmitted electrons are caused to
collide with the reflecting plate RF. Therefore, a scattering angle
diaphragm ASA3 that limits a scattering angle needs to be provided
immediately below the sample SAM. Thus, it is difficult to acquire
a transmission electron image having only a small scattering angle
(for example, 75 mrad or less) . On the other hand, a configuration
of reducing the size of the scattering angle diaphragm ASA3 can
also be considered. However, the size of a region that can be
observed on the sample SAM is substantially the same as an aperture
of a hole of the scattering angle diaphragm ASA3, and thus a range
that can be observed is extremely small.
[0008] In addition, in general, the detector ETD includes a
scintillator and a photomultiplier tube. The secondary electrons
EB5 converted from the transmitted electrons EB4 are converted into
light by the detector ETD, the light is amplified by the
photomultiplier tube, and the amplified light is converted into an
electric signal. At this time, the signal conversion process is
performed in order of the transmitted electrons EB4, the secondary
electrons EB5, the light, and the electric signal. Therefore, the
loss during the signal conversion increases, and there is a problem
in that the yield decreases.
[0009] In JP-A-2008-66057, in order to detect transmitted
electrons, it is necessary to newly attach a high-accuracy detector
to a side of the holder. This implies that it is necessary to
reconstruct a structure and a system of a new charged particle beam
apparatus, which requires high costs.
[0010] The present invention is to provide a charged particle beam
apparatus having improved performance that can accurately obtain a
bright-field image or a dark-field image of a sample as an
observation target. In addition, another object of the present
invention is to provide a holder used in the charged particle beam
apparatus.
[0011] Other objects and new characteristics will be clarified with
reference to description of the specification and the accompanying
drawings.
[0012] The summary of a representative embodiment disclosed in the
present application will be simply described as follows.
[0013] According to one embodiment, a holder includes: a top member
that has a first hole for allowing transmission of a charged
particle beam and in which a sample is mountable in the first hole;
a bottom member that is provided to overlap with the top member in
a plan view; a side member that is connected to a part of the top
member and a part of the bottom member such that the top member and
the bottom member are separated from each other in a
cross-sectional view. In addition, the holder includes: an opening
portion that is a region surrounded by the top member, the side
member, and the bottom member; and a first scintillator that is
provided in the opening portion.
[0014] In addition, according to another embodiment, a charged
particle beam apparatus includes: a chamber; a charged particle
optical lens barrel that is attached to an upper portion of the
chamber and is capable of emitting a charged particle beam; a stage
that is attached to a lower portion of the chamber; a holder that
is provided on the stage; and a first light detector that is
positioned above the holder to be separated from the holder and is
attached to the upper portion of the chamber. Here, the holder: a
top member that has a first hole for allowing transmission of a
charged particle beam and in which a sample is mountable in the
first hole; a bottom member that is provided to overlap with the
top member in a plan view; a side member that is connected to a
part of the top member and a part of the bottom member such that
the top member and the bottom member are separated from each other
in a cross-sectional view. In addition, the holder includes: an
opening portion that is a region surrounded by the top member, the
side member, and the bottom member; and a first scintillator that
is provided in the opening portion. In addition, the first light
detector has a function capable of detecting first light that is
emitted from the first scintillator and exits from the opening
portion when the sample is mounted on the top member, the sample in
the first hole is irradiated with the charged particle beam emitted
from the charged particle optical lens barrel, and transmitted
charged particles transmitted through the sample collide with the
first scintillator.
[0015] According to the embodiments disclosed in the present
invention, the holder that can accurately obtain a bright-field
image or a dark-field image of the sample SAM as an observation
target can be provided. In addition, by using the holder, the
performance of the charged particle beam apparatus can be
improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view illustrating a holder according
to a first embodiment;
[0017] FIG. 2 is a cross-sectional view illustrating a charged
particle beam apparatus according to the first embodiment;
[0018] FIG. 3 is a cross-sectional view illustrating a charged
particle beam apparatus according to Modification Example 1;
[0019] FIG. 4 is a perspective view illustrating an optical member
according to a second embodiment;
[0020] FIG. 5 is a perspective view illustrating the holder
including the optical member according to the second
embodiment;
[0021] FIG. 6 is a cross-sectional view illustrating a charged
particle beam apparatus according to the second embodiment;
[0022] FIG. 7 is a cross-sectional view illustrating a charged
particle beam apparatus according to a third embodiment;
[0023] FIG. 8 is a perspective view illustrating an optical member
according to a fourth embodiment;
[0024] FIG. 9 is a perspective view illustrating an optical member
according to the fourth embodiment;
[0025] FIG. 10 is a perspective view illustrating the holder
including the optical member according to the fourth
embodiment;
[0026] FIG. 11 is a plan view illustrating the holder including the
optical member according to the fourth embodiment;
[0027] FIG. 12 is a cross-sectional view illustrating the holder
including the optical member according to the fourth
embodiment;
[0028] FIG. 13 is a cross-sectional view illustrating a charged
particle beam apparatus according to the fourth embodiment;
[0029] FIG. 14 is a cross-sectional view illustrating the charged
particle beam apparatus according to the fourth embodiment;
[0030] FIG. 15 is a cross-sectional view illustrating a charged
particle beam apparatus according to a fifth embodiment;
[0031] FIG. 16 is a cross-sectional view illustrating a charged
particle beam apparatus according to a sixth embodiment;
[0032] FIG. 17 is a perspective view illustrating an optical member
according to a seventh embodiment;
[0033] FIG. 18 is a perspective view illustrating the optical
member according to the seventh embodiment;
[0034] FIG. 19 is a perspective view illustrating the holder
including the optical member according to the seventh
embodiment;
[0035] FIG. 20 is a cross-sectional view illustrating the holder
including the optical member according to the seventh embodiment;
and
[0036] FIG. 21 is a schematic cross-sectional view illustrating a
charged particle beam apparatus of the prior art.
DESCRIPTION OF EMBODIMENTS
[0037] Hereinafter, an embodiment of the present invention will be
described in detail based on the drawings. In all the diagrams for
describing the embodiment, members having the same functions are
represented by the same reference numerals, and the description
thereof will not be repeated. In the following embodiment,
basically, the description of the same or identical portions will
not be repeated.
First Embodiment
[0038] Hereinafter, a holder HL according to a first embodiment and
a charged particle beam apparatus 100 including the holder HL will
be described using FIGS. 1 and 2. The charged particle beam
apparatus 100 is, for example, a scanning electron microscope
(SEM). FIG. 1 is a perspective view illustrating the external
appearance of the holder HL. FIG. 2 is a cross-sectional view
illustrating the charged particle beam apparatus 100 and also
illustrating the detailed cross-sectional structure of the holder
HL.
[0039] As illustrated in FIG. 1, the holder HL according to the
first embodiment includes a top member HLt, a side member HLs, and
a bottom member HLb. The bottom member HLb is provided to overlap
with the top member HLt in a plan view, and the side member HLs is
connected to a part of the top member HLt and a part of the bottom
member HLb such that the top member HLt and the bottom member HLb
are separated from each other in a cross-sectional view. In the
vicinity of the top member HLt, a hole TH1 for allowing
transmission of a charged particle beam EB1 illustrated in FIG. 2
is provided to penetrate the top member HLt.
[0040] An opening portion OP is a region surrounded by the top
member HLt, the side member HLs, and the bottom member HLb. In the
opening portion OP, a scattering angle diaphragm ASA1 and a
scintillator SC1 are provided. The scattering angle diaphragm ASA1
partially covers a surface of the scintillator SC1 such that only
transmitted charged particles having a specific scattering angle
collide with the scintillator SC1. In the first embodiment, a case
where the scattering angle diaphragm ASA1 and the scintillator SC1
are provided on the bottom member HLb is described as an
example.
[0041] A planar shape of the holder HL is a circular shape or an
elliptical shape. In a portion where the side member HLs is
connected to the top member HLt and the bottom member HLb, a notch
NC1 is provided on an inner wall of each of the top member HLt and
the bottom member HLb. Therefore, in the opening portion OP, a
planar shape of the inner wall of each of the top member HLt and
the bottom member HLb is a shape that is obtained by providing the
notch NC1 in a part of the circular shape or the elliptical
shape.
[0042] In addition, a material forming each of the members (the top
member HLt, the side member HLs, and the bottom member HLb) forming
the holder HL is a metal such as aluminum or an alloy such as
stainless steel. In addition, the material forming the holder HL
has a function of not allowing light and an X-ray. In addition, the
light is light from a vacuum-ultraviolet range to a visible range.
In the first embodiment, a case where the top member HLt, the side
member HLs, and the bottom member HLb are integrated with each
other is described as an example. However, these members may be
formed as different members.
[0043] As illustrated in FIG. 2, in the top member HLt, a sample
SAM is mounted in the hole TH1. The top member HLt includes a table
TB and a cap CP that is provided on the table TB. The table TB is
provided to mount a mesh MS on which the sample SAM is provided,
and the cap CP is provided to hold the sample SAM and the mesh
MS.
[0044] The charged particle beam apparatus 100 includes: a chamber
1; a charged particle optical lens barrel 2 that is attached to an
upper portion of the chamber 1; a stage 3 that is attached to a
lower portion of the chamber 1; the holder HL that is provided on
the stage 3; and a light detector 4 that is positioned above the
holder HL to be separated from the holder HL and is attached to the
upper portion of the chamber 1.
[0045] The charged particle optical lens barrel 2 includes: an
electron gun for emitting a charged particle beam (electron beam);
a condenser lens; and a scan coil for controlling scanning in a
horizontal direction. The charged particle beam (electron beam) EB1
is emitted from the charged particle optical lens barrel 2 and is
irradiated toward the sample SAM.
[0046] The stage 3 is a base for mounting the holder HL and
includes a mechanism of adjusting a position in a thickness and a
horizontal direction and a mechanism for rotation in a horizontal
direction. By rotating the stage 3, a direction of the holder HL
mounted on the stage 3 can be changed. In addition, a material
forming the stage 3 is the same as the material forming each of the
members of the holder HL. In addition, in the first embodiment, the
holder HL is freely detachable from the stage 3.
[0047] The light detector 4 has a function capable of detecting
light LI1 that is emitted from the scintillator SC1 and exits from
the opening portion OP of the holder HL. This function will be
described below in detail.
[0048] An image processing apparatus 6 is connected to the light
detector 4 and has a function of converting transmitted charged
particle information included in the light LI1 into a transmitted
charged particle image. The image processing apparatus 6 includes,
for example, a photomultiplier tube, an amplifier circuit, and an
A/D converter and converts an optical signal into an electric
signal using these components. That is, the light LI1 is converted
into image data regarding a transmitted charged particle image by
the image processing apparatus 6. The image data is visibly
recognized by a display device provided inside or outside the image
processing apparatus 6. The image processing apparatus 6 may be
attached to the inside of the charged particle beam apparatus 100
or may be attached to the outside of the charged particle beam
apparatus 100.
[0049] Hereinafter, a method for observing the transmitted charged
particle image of the sample SAM using the charged particle beam
apparatus 100 in the first embodiment will be described. In the
first embodiment, a case where a dark-field image of the sample SAM
is observed will be described. The observation of the transmitted
charged particle image of the sample SAM in the first embodiment is
performed in a state where the internal pressure of the chamber 1
is set in a range of 1.times.10.sup.-6 Pa to 3000 Pa and the inside
of the chamber 1 is filled with air, nitrogen gas, or the like.
[0050] First, the holder HL where the sample SAM as an observation
target is mounted on the mesh MS is prepared, and the holder HL is
fixed to the stage 3. Next, the charged particle beam (electron
beam) EB1 is emitted from the charged particle optical lens barrel
2. The charged particle beam EB1 passes through the hole TH1 of the
holder HL along an optical axis OA and is irradiated on the sample
SAM. The charged particle beam EB1 is scattered in the sample SAM
and transmits downward through the sample SAM. Transmitted charged
particles (transmitted electrons) EB2 having transmitted through
the sample SAM reach the scattering angle diaphragm ASA1 in the
opening portion OP of the holder HL. The scattering angle diaphragm
ASA1 is set such that only transmitted charged particles EB2 having
a specific scattering angle transmit through the scattering angle
diaphragm ASA1. The transmitted charged particles EB2 having
transmitted through the scattering angle diaphragm ASA1 collide
with the scintillator SC1 in the opening portion OP of the holder
HL.
[0051] When the transmitted charged particles EB2 collide with the
scintillator SC1, kinetic energy of the transmitted charged
particles EB2 is converted into light energy, and the light LI1 is
emitted from the scintillator SC1. The light LI1 exits from the
opening portion OP and is detected by the light detector 4. The
light LI1 detected by the light detector 4 is input as an optical
signal to the image processing apparatus 6 connected to the light
detector 4.In the image processing apparatus 6, an optical signal
is converted into an electric signal. As a result, image data is
generated as a transmitted charged particle image, and the
transmitted charged particle image (dark-field image) of the sample
SAM can be observed by checking the image data using a display
device or the like.
[0052] In addition, the light LI1 emitted from the scintillator SC1
in the first embodiment is light from a vacuum-ultraviolet range to
a visible range and has the same transmitted charged particle
information as that of the transmitted charged particles EB2.
Therefore, as described above, the transmitted charged particle
image can be checked by the image processing apparatus 6 based on
the light LI1.
[0053] Hereinafter, characteristics of the light detector 4 and the
light LI1 used in the first embodiment will be described.
[0054] The light detector 4 is called a ultra-variable pressure
detector (UVD) and is the same detector as disclosed in
JP-A-2013-225530 or a detector capable of detecting light. In
particular, the UVD is used for observing a low vacuum, and the
observation of a low vacuum is performed in a state where the
internal pressure of the chamber 1 is set as, for example, 30 Pa
and the inside of the chamber 1 is filled with air, nitrogen gas,
or the like. the observation of a low vacuum is performed mainly in
order to remove charge during observation of an insulated sample.
The UVD is mounted on a large number of electron microscopes.
[0055] Hereinafter, the observation of a low vacuum using the light
detector 4 disclosed in JP-A-2013-225530 will be described. In
JP-A-2013-225530, in order to catch an amplified signal of
secondary electron gas, a voltage of several hundreds of V is
applied to a bias electrode arranged in the vicinity of the light
detector 4. As a result, when an electric field is formed between
the bias electrode and the sample SAM, secondary electrons
generated from a surface of the sample SAM are accelerated, and the
secondary electrons collide with residual gas molecules, and the
residual gas molecules are ionized into positive ions and
electrons. Exciting light generated at this time is detected by the
light detector 4 such that a secondary electron image of a target
in a low vacuum is formed.
[0056] The light detector 4 (UVD) in the first embodiment is
originally set to detect fine exciting light and may be a
high-sensitivity light detector. The light detector 4 can also
detect exciting light as described above. However, a transmission
electron image is formed using the light LI1 instead of using
exciting light. In other words, the light detector 4 detects the
light LI1 in an environment where exciting light is not detected.
In order to enable the method to be performed, the voltage of the
bias electrode arranged in the vicinity of the light detector 4 is
set off (0 V). At this time, the environment in the chamber 1 may
be either a low vacuum or a high vacuum. In the first embodiment,
the light detector 4 detects only the light LI1 emitted from the
scintillator SC1, and thus an accurate transmitted charged particle
image can be obtained.
[0057] In this way, with the holder HL according to the first
embodiment, the transmitted charged particles EB2 are converted
into the light LI1, and the light LI1 can be converted into an
electric signal by the photomultiplier tube connected to the light
detector 4. That is, the signal conversion process is performed in
order of the transmitted charged particles EB2, the light LI1, and
the electric signal. Therefore, the loss during the signal
conversion is small, the yield can be improved.
[0058] In addition, the contrast of the transmission electron image
varies largely by changing the scattering angle. For example, when
metal nanoparticles are observed, the contrast is inverted between
a scattering angle of 0 mrad to 75 mrad and a scattering angle of
300 mrad to 600 mrad. Therefore, in order to acquire a clear
transmission electron image, it is important to control the
scattering angle. In particular, when the acceleration voltage of
the charged particle beam EB1 is 30 kV, in a bright-field
observation, a scattering angle of 75 mrad or less is necessary in
many cases. When the scattering angle is controlled in a portion
that is as distant from the sample SAM as possible, the accuracy of
the control of the scattering angle is improved. Therefore, in the
first embodiment, by providing the scattering angle diaphragm ASA1
as a mask on the scintillator SC1, a range where the transmitted
charged particles EB2 collide with the scintillator SC1 is limited.
That is, by changing the shape of the scattering angle diaphragm
ASA1 as a mask, the scattering angle that can be detected can be
easily controlled.
[0059] In the first embodiment, the scintillator SC1 in the bottom
member HLb is partially covered with the scattering angle diaphragm
ASA1, and the scattering angle diaphragm ASA1 can be changed to a
scattering angle diaphragm corresponding to a desired scattering
angle including a dark field.
[0060] In this way, with the charged particle beam apparatus 100
according to the first embodiment, a bright-field image or a
dark-field image of the sample as an observation target can be
accurately obtained. In addition, the reason why the
above-described effect is obtained is that the holder HL is
provided including: the top member HLt on which the sample SAM is
mountable; and the scintillator SC1 that is provided in the opening
portion OP. In other words, according to the first embodiment, the
holder HL that can accurately obtain a bright-field image or a
dark-field image of the sample SAM as an observation target can be
provided. In addition, by using the holder HL, the performance of
the charged particle beam apparatus 100 can be improved.
[0061] In addition, as described above, in the first embodiment,
using the light detector 4 that is attached to the upper portion of
the chamber 1, the light LI1 that is emitted from the scintillator
SC1 and exits from the opening portion OP of the holder HL can be
detected. Accordingly, it is not necessary to connect a cable or
the like to the holder HL. That is, in order to detect the light
LI1, it is required to newly introduce a dedicated light detector,
to develop a structure of a new charged particle beam apparatus,
and to reconstruct a detection system. Therefore, costs for the
requirements can be reduced.
MODIFICATION EXAMPLE 1
[0062] Hereinafter, the holder HL according to Modification Example
1 of the first embodiment and the charged particle beam apparatus
100 including the holder HL will be described using FIG. 3.
[0063] In the first embodiment, the case where the dark-field image
of the sample SAM is observed has been described. In Modification
Example 1, a case where a bright-field image of the sample SAM is
observed will be described. Therefore, in Modification Example 1, a
scattering angle diaphragm ASA2 is used instead of the scattering
angle diaphragm ASA1 in the first embodiment. In addition, the
scintillator SC2 in Modification Example 1 has the same properties
as the scintillator SC1 in the first embodiment.
[0064] As illustrated in FIG. 3, in Modification Example 1, the
charged particle beam EB1 is scattered in the sample SAM or
transmits downward through the sample SAM without being scattered.
Transmitted charged particles EB3 having transmitted through the
sample SAM transmit the scattering angle diaphragm ASA2 and collide
with the scintillator SC2 in the opening portion OP of the holder
HL.
[0065] The transmitted charged particles EB3 in Modification
Example 1 transmit through the inside of the opening portion OP at
a smaller scattering angle than the transmitted charged particles
EB2 in the first embodiment. That is, an angle formed between a
direction in which the transmitted charged particles EB3 transmit
and the optical axis OA is smaller than an angle formed between a
direction in which the transmitted charged particles EB2 transmit
and the optical axis OA. Therefore, in the holder HL in
Modification Example 1, for the transmitted charged particles EB3
transmitted at a small scattering angle, the scattering angle
diaphragm ASA2 is provided instead of the scattering angle
diaphragm ASA1. The scattering angle diaphragm ASA2 in Modification
Example 1 is set such that only the transmitted charged particles
EB3 transmit therethrough.
[0066] When the transmitted charged particles EB3 collide with the
scintillator SC2, kinetic energy of the transmitted charged
particles EB3 is converted into light energy, and light LI2 is
emitted from the scintillator SC2. The light LI2 exits from the
opening portion OP and is detected by the light detector 4. A
transmitted charged particle image (bright-field image) of the
sample SAM is obtained by the image processing apparatus 6 based on
the detected light LI2.
[0067] This way, even in Modification Example 1, substantially the
same effect as that of the first embodiment can be obtained except
for a difference between the dark-field image and the bright-field
image.
Second Embodiment
[0068] Hereinafter, an optical member (member) OM1 according to a
second embodiment, a holder HL including the optical member OM1,
and a charged particle beam apparatus 200 including the holder HL
will be described using FIGS. 4 to 6. Hereinafter, a difference
between the second embodiment and the first embodiment will be
mainly described.
[0069] In the second embodiment, the optical member OM1 is attached
to the holder HL described in FIG. 1. FIG. 4 is a perspective view
illustrating the external appearance of the optical member OM1,
FIG. 5 is a perspective view illustrating the holder HL to which
the optical member OM1 is attached, and FIG. 6 is a cross-sectional
view illustrating the charged particle beam apparatus 200 including
the holder HL.
[0070] As illustrated in FIG. 4, the optical member OM1 includes a
light guide LG1 in which a hole TH2 is provided. The light guide
LG1 has a function of allowing transmission of light and not
allowing transmission of an X-ray. A material forming the light
guide LG1 is, for example, glass or an acrylic resin.
[0071] In addition, a planar shape of the optical member OM1 (the
light guide LG1) is a shape that is obtained by providing a notch
NC2 in a part of a circular shape or an elliptical shape. In other
words, the optical member OM1 is a cylinder that is obtained by
providing the notch NC2 in a part of a circular cylinder or an
elliptical cylinder.
[0072] As illustrated in FIG. 5, the optical member OM1 is provided
in the opening portion OP of the holder HL. At this time, a part of
the light guide LG1 is covered with the side member HLs of the
holder HL, and the other portion of the light guide LG1 is exposed
from the side member HLs. The notch NC2 of the optical member OM1
is the portion covered with the side member HLs and is positioned
in the opening portion OP so as to correspond to the notch NC1 of
the holder HL. That is, the optical member OM1 is provided in the
opening portion OP such that the notch NC2 is in contact with the
side member HLs . As a result, when the optical member OM1 is
attached to the holder HL, alignment between the optical member OM1
and the holder HL is simple.
[0073] In addition, the hole TH2 of the optical member OM1 overlaps
with the hole TH1 of the holder HL in a plan view, and the aperture
of the hole TH2 is larger than the aperture of the hole TH1.
[0074] As illustrated in FIG. 6, the charged particle beam EB1
emitted from the charged particle optical lens barrel 2 transmits
through the hole TH1, is irradiated on the sample SAM, is scattered
in the sample SAM, and transmits downward through the sample SAM.
The scintillator SC1 is provided between the light guide LG1 and
the bottom member HLb such that a part of the scintillator SC1 is
exposed in the hole TH2. The transmitted charged particles EB2
transmit through the scattering angle diaphragm ASA1 in the hole
TH2 and collide with the scintillator SC1.
[0075] The light LI1 emitted from the scintillator SC1 transmits
through the inside of the light guide LG1, exits from the opening
portion OP such that a side surface LGls of the light guide LG1 is
an exit surface, and is detected by the light detector 4.
[0076] Since the light guide LG1 includes the hole TH2, the side
surface of the light guide LG1 includes an inner diameter surface
moving along the hole TH2 and an outer diameter surface
corresponding to an outer wall of the light guide LG1. "The side
surface of the light guide LG1" described in the present invention
refers to the outer diameter surface of the light guide LG1.
Therefore, the reference numeral LG1s is used for both the side
surface of the light guide LG1 and the exit surface of the Light
LI1.
[0077] As described above, the light guide LG1 has a function of
allowing transmission of light. Here, the light LI1 emitted from
the scintillator SC1 is light from a vacuum-ultraviolet range to a
visible range. Accordingly, it can also be said that the light
guide LG1 has a function of allowing transmission of the light from
a vacuum-ultraviolet range to a visible range.
[0078] However, during the observation of the sample SAM, it may be
required to detect an X-ray emitted from the sample SAM and to
analyze an element included in the sample SAM. Therefore, as
illustrated in FIG. 6, the X-ray detector 5 is positioned above the
holder HL to be separated from the holder HL and is attached to the
upper portion of the chamber 1 of the charged particle beam
apparatus 200. The X-ray detector 5 is generally called an EDS
(Energy Dispersive X-ray Spectrometry) detector.
[0079] When a specific portion of the sample SAM is irradiated with
the charged particle beam EB1, a characteristic X-ray having
information unique to an element is generated. By detecting the
characteristic X-ray using the EDS detector to measure the energy
and intensity of the characteristic X-ray, an element forming the
specific portion can be qualitatively analyzed. In the present
invention, for example, X-rays XR1 to XR3 described below are the
above-described characteristic X-rays.
[0080] As illustrated in FIG. 6, when the sample SAM is irradiated
with the charged particle beam EB1, the X-ray XR1 is emitted from
the sample SAM. When the transmitted charged particles EB2 collide
with the scintillator SC1, the X-ray XR2 is emitted from the
scintillator SC1. In order to analyze the element included in the
sample SAM, the X-ray XR1 only needs to be detected. However, when
the X-ray detector 5 also detects the X-ray XR2, there is a problem
in that appropriate element analysis cannot be performed.
[0081] Therefore, as described above, the light guide LG1 in the
second embodiment has a function of not allowing transmission of an
X-ray. Therefore, the X-ray detector 5 can detect only the X-ray
XR1 without detecting the X-ray XR2. When the thickness of the
light guide LG1 is extremely small, the X-ray XR2 may transmit
through the light guide LG1. Therefore, it is preferable that the
light guide LG1 is formed at a sufficient thickness such that the
X-ray XR2 cannot transmit through the light guide LG1.
Third Embodiment
[0082] Hereinafter, a charged particle beam apparatus 300 including
the holder HL according to a third embodiment will be described
using FIG. 7. Hereinafter, a difference between the third
embodiment and the second embodiment will be mainly described.
[0083] In the second embodiment, the mesh MS for providing the
sample SAM on the top member HLt of the holder HL is provided.
However, in the third embodiment, the top member HLt is not
provided on the holder HL, and a rotary table 3d that is a part of
the stage 3 is provided instead of the top member HLt. That is, the
hole TH1, the mesh MS, and the sample SAM mounted on the mesh MS
are provided in the rotary table 3d.
[0084] The stage 3 in the third embodiment includes a base portion
3a, a rotation portion 3b, a pillar portion 3c, and the rotary
table 3d. The base portion 3a is attached to the lower portion of
the chamber and includes a mechanism of adjusting a position in a
thickness and a horizontal direction and a mechanism for rotation
in a horizontal direction. The rotation portion 3b includes a
mechanism for rotating the pillar portion 3c and can rotate the
rotary table 3d through the pillar portion 3c. The pillar portion
3c is connected to the rotation portion 3b and the rotary table 3d.
In addition, when the sample SAM is replaced, the pillar portion 3c
and the rotary table 3d can be easily removed from the stage 3 (the
rotation portion 3b).
[0085] The rotary table 3d includes the table TB and the cap CP as
in the top member HLt in the second embodiment and has a wider
surface area than the top member HLt in the second embodiment. In
the rotary table 3d, a plurality of holes TH1 are provided, and the
mesh MS and the sample SAM can be provided in each of the holes
TH1.
[0086] In addition, the holder HL in the third embodiment includes
the side member HLs and the bottom member HLb without including the
top member HLt as described above. Therefore, in the third
embodiment, the opening portion OP is a region surrounded by the
rotary table 3d that is a part of the stage 3, the side member HLs,
and the bottom member HLb. In addition, in the opening portion OP,
the optical member OM1 is provided as in the second embodiment, and
the scintillator SC1 is provided between the light guide LG1 and
the bottom member HLb.
[0087] For example, by rotating the rotation portion 3b of the
stage 3 after observing one sample SAM, the rotary table 3d can be
rotated to observe the following sample SAM. By using the holder HL
according to the third embodiment and the charged particle beam
apparatus 300, for example, time and effort required to return the
internal pressure of the chamber 1 to the atmospheric pressure, to
replace the holder HL with another holder HL on which the following
sample SAM is mounted, and to adjust the internal pressure of the
chamber 1 whenever each of a plurality of the samples SAM is
observed can be reduced.
Fourth Embodiment
[0088] Hereinafter, an optical member (member) OM2 according to a
fourth embodiment, a holder HL including the optical member OM2,
and a charged particle beam apparatus 400 including the holder HL
will be described using FIGS. 8 to 14. Hereinafter, a difference
between the fourth embodiment and the first embodiment or the
second embodiment will be mainly described.
[0089] In the fourth embodiment, the optical member OM2 is attached
to the holder HL described in FIG. 1. FIG. 8 is a perspective view
illustrating the external appearance of the optical member OM2,
FIG. 9 is a perspective view illustrating the external appearance
of a side of the optical member OM2 opposite to that of FIG. 8,
FIG. 10 is a perspective view illustrating the holder HL to which
the optical member OM2 is attached, and FIG. 11 is a plan view
illustrating rough positions of an exit surface LG2s of a light
guide LG2 and an exit surface LG3s of a light guide LG3. In
addition, FIG. 12 is a detailed cross-sectional view illustrating
the holder HL including the optical member OM2, and FIG. 13 is a
cross-sectional view illustrating the charged particle beam
apparatus 400 including the holder HL.
[0090] As illustrated in FIGS. 8 and 9, the optical member OM2
includes the light guide LG2 and the light guide LG3 in which a
hole 3 and a hole TH4 are provided. The light guide LG2 and the
light guide LG3 have a function of allowing transmission of light
and not allowing transmission of an X-ray as in the light guide LG1
in the second embodiment. A material forming the light guide LG2
and the light guide LG3 is, for example, glass or an acrylic
resin.
[0091] In addition, a side surface of each of the light guide LG2
and the light guide LG3 is partially covered with a blocking layer
BL. A material forming the blocking layer BL is the same as that of
the holder HL and the stage 3 and is a metal such as aluminum or an
alloy such as stainless steel. In addition, the material forming
the blocking layer BL has a function of not allowing light and an
X-ray. In addition, the light is light from a vacuum-ultraviolet
range to a visible range.
[0092] In addition, as in the optical member OM1 in the second
embodiment, a planar shape of the optical member OM2 is a shape
that is obtained by providing a notch NC2 in a part of a circular
shape or an elliptical shape. In other words, the optical member
OM2 is a cylinder that is obtained by providing the notch NC2 in a
part of a circular cylinder or an elliptical cylinder.
[0093] In the optical member OM2, the blocking layer BL is provided
on the side surface of each of the light guide LG2 and the light
guide LG3. Therefore, in the planar shape of the optical member
OM2, a thin step (unevenness) is formed in a part of an arc of a
circular shape or an elliptical shape. Thus, to be exact, the
planar shape of each of the light guide LG2 and the light guide LG3
refers to a shape that is obtained by providing the notch NC2 in a
part of a circular shape or an elliptical shape. However, here, in
the description of the planar shape, the notch NC2 is important.
Therefore, in the fourth embodiment, this small difference is
recognized as an error, and the planar shape of the optical member
OM2 is defined as a shape that is obtained by providing the notch
NC2 in a part of a circular shape or an elliptical shape.
[0094] As illustrated in FIG. 10, the optical member OM2 is
provided in the opening portion OP of the holder HL. At this time,
the notch NC2 of the optical member OM2 is the portion covered with
the side member HLs and is positioned in the opening portion OP so
as to correspond to the notch NC1 of the holder HL. That is, the
optical member OM2 is provided in the opening portion OP such that
the notch NC2 is in contact with the side member HLs. As a result,
when the optical member OM2 is attached to the holder HL, alignment
between the optical member OM2 and the holder HL is simple.
[0095] In addition, the hole TH3 and the hole TH4 of the optical
member OM2 overlap with the hole TH1 of the holder HL in a plan
view.
[0096] In the fourth embodiment, the portion of the optical member
OM2 provided along the notch NC2 is covered with the blocking layer
BL. However, as illustrated in FIG. 10, this portion is also
covered with the side member HL of the holder HL. Therefore, in the
portion, the blocking layer BL is not essential and is not
necessarily provided.
[0097] As described above, the side surface of each of the light
guide LG2 and the light guide LG3 is partially covered with the
side member HLs of the holder HL and the blocking layer BL. In
other words, in a plan view, the respective side surfaces of the
light guide LG2 and the light guide LG3 are divided by the side
member HLs and the blocking layer BL. As illustrated in FIG. 11,
the side surface (exit surface) LG2s of the light guide LG2 and the
side surface (exit surface) LG3s of the light guide LG3 are
positioned opposite to each other and are exposed at given aperture
angles. The aperture angles of the exit surface LG2s and the exit
surface LG3s correspond to central angles with respect to the
center of the optical member OM2 (the center of the hole TH3 and
the center of the hole TH4). In the fourth embodiment, each of the
aperture angles is set to be 60 to 120 degrees in consideration of
a range where the light LI2 and light LI3 exit. FIG. 11 illustrates
a case where the aperture angle is 120 degrees.
[0098] The light guide LG2 or the light guide LG3 has the hole TH3
or the hole TH4. Therefore, as in the light guide LG1 in the second
embodiment, "the side surface of the light guide LG2" or "the side
surface of the light guide LG3" described in the present invention
refers to the outer diameter surface of the light guide LG2 or the
light guide LG3. Therefore, as described above, the reference
numeral LG2s is used for both the side surface of the light guide
LG2 and the exit surface of the Light LI1, and the reference
numeral LG3s is used for both the side surface of the light guide
LG3 and the exit surface of the Light LI2.
[0099] As illustrated in FIGS. 12 and 13, the blocking layer BL is
provided between the light guide LG2 and the light guide LG3 such
that the light guide LG2 and the light guide LG3 are not in contact
with each other. As a result, the light LI2 having transmitted
through the inside of the light guide LG2 and the light LI3 having
transmitted through the inside of the light guide LG3 can be
prevented from interfering each other.
[0100] In addition, the hole TH3 is provided in the light guide
LG2, and the hole TH4 that communicates with the hole TH3 and has a
narrower aperture than the hole TH3 is provided in the light guide
LG2, in the blocking layer BL, and in the light guide LG3. The
aperture of the hole TH3 is wider than the aperture of each of the
hole TH1 and the hole TH4.
[0101] The scintillator SC1 is provided on the light guide LG2
positioned in the vicinity of the hole TH4 in the hole TH3 and is
in direct contact with the light guide LG2 . The scintillator SC2
is provided between the light guide LG3 and the bottom member HLb
such that a part of the scintillator SC2 is exposed in the hole
TH4, and is in direct contact with the light guide LG3. Therefore,
the light LI1 emitted from the scintillator SC1 directly propagates
in the light guide LG2, and the light LI2 emitted from the
scintillator SC2 directly propagates in the light guide LG3.
[0102] In addition, in order to reflect the light LI1 and the light
LI2, a reflecting film (mirror film) RF is provided between the
light guide LG2 and the blocking layer BL and between the light
guide LG3 and the blocking layer BL. A material forming the
reflecting film RF is, for example, a metal such as aluminum or an
alloy such as brass. In the fourth embodiment, the reflecting film
RF is provided such that each of the light LI1 propagating in the
light guide LG2 and the light LI2 propagating in the light guide
LG3 is attenuated. However, when the object is sufficiently
achieved by the blocking layer BL, the reflecting film RF is not
essential and is not necessarily provided. For example, by
performing mirror-like finishing on the surface of the blocking
layer BL, the same function as that of the reflecting film RF can
also be imparted to the blocking layer BL.
[0103] As illustrated in FIGS. 12, 13, and 14, the charged particle
beam EB1 emitted from the charged particle optical lens barrel 2
transmits through the hole TH1, is irradiated on the sample SAM, is
scattered in the sample SAM, and transmits downward through the
sample SAM. Among the transmitted charged particles having
transmitted through the sample SAM, the transmitted charged
particles EB2 having transmitted at a relatively large scattering
angle collide with the scintillator SC1 in the hole TH3, and the
transmitted charged particles EB3 having transmitted at a
relatively small scattering angle collide with the scintillator SC2
in the hole TH4. In other words, an angle formed between a
direction in which the transmitted charged particles EB3 transmit
and the optical axis OA is smaller than an angle formed between a
direction in which the transmitted charged particles EB2 transmit
and the optical axis OA, the transmitted charged particles EB2
collide with the scintillator SC1 in the hole TH3, and the
transmitted charged particles EB3 transmit through the scattering
angle diaphragm ASA2 in the hole TH4 and collide with the
scintillator SC2.
[0104] FIG. 13 illustrates a case where the light LI1 is detected.
The light LI1 emitted from the scintillator SC1 transmits through
the inside of the light guide LG2, exits from the opening portion
OP such that the side surface LG2s of the light guide LG2 is an
exit surface, and is detected by the light detector 4.
[0105] FIG. 14 illustrates a case where the light LI2 is detected.
First, by rotating the stage 3 in the state of FIG. 13, the holder
HL is rotated. In this case, as illustrated in FIG. 14, the light
LI2 emitted from the scintillator SC2 transmits through the inside
of the light guide LG3, exits from the opening portion OP such that
the side surface LG3s of the light guide LG3 is an exit surface,
and is detected by the light detector 4.
[0106] As described above, the light guide LG2 and the light guide
LG3 have a function of allowing transmission of light. Here, the
light LI1 emitted from the scintillator SC1 and the light LI2
emitted from the scintillator SC2 are light from a
vacuum-ultraviolet range to a visible range. Accordingly, it can
also be said that the light guide LG2 and the light guide LG3 have
a function of allowing transmission of the light from a
vacuum-ultraviolet range to a visible range.
[0107] However, in the fourth embodiment, as in the second
embodiment, during the observation of the sample SAM, it may be
required to detect an X-ray emitted from the sample SAM and to
analyze an element included in the sample SAM. Therefore, as
illustrated in FIGS. 13 and 14, the same X-ray detector 5 as that
of the second embodiment is attached to the chamber 1 of the
charged particle beam apparatus 400.
[0108] Here, when the sample SAM is irradiated with the charged
particle beam EB1, the X-ray XR1 is emitted from the sample SAM.
When the transmitted charged particles EB2 collide with the
scintillator SC1, the X-ray XR2 is emitted from the scintillator
SC1. When the transmitted charged particles EB3 collide with the
scintillator SC2, the X-ray XR3 is emitted from the scintillator
SC2.
[0109] The light guide LG2 and the light guide LG3 in the fourth
embodiment have a function of not allowing transmission of an
X-ray. Therefore, the X-ray detector 5 can detect only the X-ray
XR1 without detecting the X-ray XR2 the X-ray XR3. When the
thicknesses of the light guide LG2 and the light guide LG3 are
extremely small, the X-ray XR2 and the X-ray XR3 may transmit
therethrough. Therefore, it is preferable that the light guide LG2
and the light guide LG3 are formed at sufficient thicknesses such
that the X-ray XR2 and the X-ray XR3 cannot transmit
therethrough.
[0110] In addition, each of the blocking layer BL and the holder HL
is formed of a metal material or an alloy material and has a
function of not allowing transmission of light and an X-ray.
Therefore, in the fourth embodiment, the light LI1 and the light
LI2 exit from the exit surface LG2s and the exit surface LG3s,
respectively, without being mixed with each other. Accordingly, the
light LI1 and the light LI2 can be accurately detected by the light
detector 4 . The X-ray XR2 and the X-ray XR3 can be blocked by the
light guide LG2, the light guide LG3, the blocking layer BL, and
the holder HL.
[0111] In addition, in the fourth embodiment, the light LI1 and the
light LI2 can be simultaneously emitted from the transmitted
charged particles EB3 and the transmitted charged particles EB4
having different scattering angles. By rotating the stage 3 without
extracting the holder HL from the chamber 1, each of the light LI1
and the light LI2 can be detected by the light detector 4.
[0112] For example, in the first embodiment or the second
embodiment, in order to obtain both a dark-field image and a
bright-field image from one sample, it is necessary to replace the
holder HL with another holder HL and to replace the scintillator
SC1 and the scattering angle diaphragm ASA1 with the scintillator
SC2 and the scattering angle diaphragm ASA2. On the other hand, in
the fourth embodiment, both a dark-field image and a bright-field
image can be obtained without replacing the holder HL or the
like.
[0113] In particular, when a structure as an observation target in
the sample SAM is a nanometer-sized structure and it is desired to
obtain both a dark-field image and a bright-field image from this
structure, it is extremely difficult to specify completely the same
subject and to find out completely the same observation point
whenever the replacement of the holder HL or the like is performed.
By using the holder HL including the optical member OM2 as in the
fourth embodiment, the above-described problem can be prevented,
and a high-accuracy dark-field image and a high-accuracy
bright-field image can be obtained.
Fifth Embodiment
[0114] Hereinafter, a charged particle beam apparatus 500 according
to a fifth embodiment will be described using FIG. 15. Hereinafter,
a difference between the fifth embodiment and the fourth embodiment
will be mainly described.
[0115] In the fifth embodiment, as in the fourth embodiment, the
optical member OM2 described in FIGS. 8 and 9 is attached to the
holder HL described in FIG. 1. However, in the fifth embodiment,
unlike the fourth embodiment, as illustrated in FIG. 15, two light
detectors including a light detector 4a and a light detector 4b are
positioned above the holder HL to be separated from the holder HL
and are attached to the upper portion of the chamber 1. The light
detector 4a and the light detector 4b have the same function as the
light detector 4 in the fourth embodiment and are connected to the
same image processing apparatus 6.
[0116] The light detector 4a and the light detector 4b face the
light guide LG2 and the light guide LG3, respectively, and are
positioned opposite to each other with the holder HL interposed
therebetween. That is, the light detector 4a is positioned closer
to the exit surface LG2s of the light guide LG2 than the light
detector 4b, and the light detector 4b is positioned closer to the
exit surface LG3s of the light guide LG3 than the light detector
4a.
[0117] The light LI1 emitted from the exit surface LG2s is detected
by the light detector 4a, and the light LI2 emitted from the exit
surface LG3s is detected by the light detector 4b. Therefore, in
the fifth embodiment, the light detector 4b is provided, and thus
the cost of the charged particle beam apparatus 500 increases as
compared to the fourth embodiment. However, the light LI1 and the
light LI2 can be detected without rotating the stage 3.
Accordingly, a dark-field image and a bright-field image of the
sample SAM can be simultaneously obtained.
Sixth Embodiment
[0118] Hereinafter, a charged particle beam apparatus 600 including
the holder HL according to a sixth embodiment will be described
using FIG. 16. Hereinafter, a difference between the sixth
embodiment and the fifth embodiment will be mainly described. In
addition, the technical thought disclosed in the sixth embodiment
is very similar to that disclosed in the third embodiment.
Therefore, in the following description, the repeated description
of the contents described in the third embodiment may be
omitted.
[0119] In the sixth embodiment, as in the fifth embodiment, the
optical member OM2, the light detector 4a, and the light detector
4b are used. However as in the third embodiment, the rotary table
3d that is a part of the stage 3 is provided instead of the top
member HLt. That is, the hole TH1, the mesh MS, and the sample SAM
mounted on the mesh MS are provided in the rotary table 3d.
[0120] As in the third embodiment, the stage 3 in the sixth
embodiment includes the base portion 3a, the rotation portion 3b,
the pillar portion 3c, and the rotary table 3d. In addition, the
holder HL in the sixth embodiment includes the side member HLs and
the bottom member HLb without including the top member HLt as
described above. Therefore, even in the sixth embodiment, the
opening portion OP is a region surrounded by the rotary table 3d
that is a part of the stage 3, the side member HLs, and the bottom
member HLb. In the opening portion OP, the optical member OM2 is
provided as in the fifth embodiment.
[0121] In the sixth embodiment, by rotating the rotation portion 3b
of the stage 3 after observing one sample SAM, the rotary table 3d
can be rotated to observe the following sample SAM. By using the
holder HL according to the third embodiment and the charged
particle beam apparatus 600, for example, time and effort required
to return the internal pressure of the chamber 1 to the atmospheric
pressure, to replace the holder HL with another holder HL on which
the following sample SAM is mounted, and to adjust the internal
pressure of the chamber 1 whenever each of a plurality of the
samples SAM is observed can be reduced.
[0122] That is, the light LI1 and the light LI2 can be
simultaneously detected, and a dark-field image and a bright-field
image of the sample SAM can be simultaneously obtained. Further,
the next sample SAM can be rapidly observed without replacing the
holder HL or the like. In addition, for the next sample SAM, the
light LI1 and the light LI2 can be simultaneously detected, and
both a dark-field image and a bright-field image of the sample SAM
can be obtained.
[0123] In the sixth embodiment, the case where two light detectors
including the light detector 4a and the light detector 4b are
provided has been described based on the fifth embodiment. However,
the charged particle beam apparatus 600 according to the sixth
embodiment is applicable to the case where the single light
detector 4 is provided as in the fourth embodiment. In this case,
the light LI1 and the light LI2 cannot be simultaneously detected.
However, since the light detector 4b is not provided, the cost of
the charged particle beam apparatus 600 can be reduced.
Seventh Embodiment
[0124] Hereinafter, an optical member (member) OM3 according to a
seventh embodiment and the holder HL including the optical member
OM3 will be described using FIGS . 17 to 20 . Hereinafter, a
difference between the seventh embodiment and the fourth embodiment
will be mainly described.
[0125] In the seventh embodiment, the optical member OM3 is
attached to the holder HL described in FIG. 1. In addition, the
charged particle beam apparatus according to the seventh embodiment
is the same as the charged particle beam apparatus 400 according to
the fourth embodiment, except that the optical member OM3 is used
instead of the optical member OM2.
[0126] FIG. 17 is a perspective view illustrating the external
appearance of the optical member OM3, FIG. 18 is a perspective view
illustrating the external appearance of a side of the optical
member OM3 opposite to that of FIG. 17, FIG. 19 is a perspective
view illustrating the holder HL to which the optical member OM3 is
attached. In addition, FIG. 20 is a detailed cross-sectional view
illustrating the holder HL including the optical member OM3.
[0127] As illustrated in FIGS. 17 and 18, the optical member OM3
includes the light guide LG2 and the light guide LG3 as in the
optical member OM2 according to the fourth embodiment. However,
positions where the blocking layer BL covers the respective side
surfaces of the light guide LG2 and the light guide LG3 are
different from those of the optical member OM2 according to the
fourth embodiment. However, the respective positions of the exit
surface LG2s of the light guide LG2 and the exit surface LG3s of
the light guide LG3 in a plan view are the same as those of FIG.
11. In addition, as in the optical member OM2 in the fourth
embodiment, a planar shape of the optical member OM3 is a shape
that is obtained by providing a notch NC2 in apart of a circular
shape or an elliptical shape. In other words, the optical member
OM3 is a cylinder that is obtained by providing the notch NC2 in a
part of a circular cylinder or an elliptical cylinder.
[0128] As illustrated in FIG. 19, the optical member OM3 is
provided in the opening portion OP of the holder HL. At this time,
the optical member OM3 is provided in the opening portion OP such
that the notch NC2 is in contact with the side member HLs. As a
result, when the optical member OM3 is attached to the holder HL,
alignment between the optical member OM3 and the holder HL is
simple.
[0129] In addition, the hole TH3 and the hole TH4 of the optical
member OM2 overlap with the hole TH1 of the holder HL in a plan
view.
[0130] In the seventh embodiment, the portion of the optical member
OM3 provided along the notch NC2 is covered with the blocking layer
BL. However, as illustrated in FIG. 19, this portion is also
covered with the side member HL of the holder HL. Therefore, in the
portion, the blocking layer BL is not essential and is not
necessarily provided.
[0131] As illustrated in FIG. 20, the blocking layer BL is provided
between the light guide LG2 and the light guide LG3 such that the
light guide LG2 and the light guide LG3 are not in contact with
each other. As a result, the light LI2 having transmitted through
the inside of the light guide LG2 and the light LI3 having
transmitted through the inside of the light guide LG3 can be
prevented from interfering each other.
[0132] In addition, the hole TH3 is provided in the light guide
LG2, and the hole TH4 that communicates with the hole TH3 and has a
narrower aperture than the hole TH3 is provided in the light guide
LG2 and in the blocking layer BL. The aperture of the hole TH3 is
wider than the aperture of each of the hole TH1 and the hole
TH4.
[0133] The scintillator SC1 is provided on the light guide LG2
positioned in the vicinity of the hole TH4 in the hole TH3 and is
in direct contact with the light guide LG2. The scintillator SC2 is
provided on the light guide LG3 such that a part of the
scintillator SC2 is exposed in the hole TH4 and the scintillator
SC2 is in direct contact with the light guide LG3. Therefore, the
light LI1 emitted from the scintillator SC1 directly propagates in
the light guide LG2, and the light LI2 emitted from the
scintillator SC2 directly propagates in the light guide LG3 in a
region below the scintillator SC2. In addition, the scattering
angle diaphragm ASA2 is provided between the scintillator SC2 and
the blocking layer BL.
[0134] The light LI1 emitted from the scintillator SC1 transmits
through the inside of the light guide LG2, exits from the opening
portion OP such that the side surface LG2s of the light guide LG2
is an exit surface, and is detected by the light detector 4. In
addition, the light LI2 emitted from the scintillator SC2 transmits
through the inside of the light guide LG3, exits from the opening
portion OP such that the side surface LG3s of the light guide LG3
is an exit surface, and is detected by the light detector 4 by
rotating the holder HL.
[0135] In order to reflect the light LI1 and the light LI2, a
reflecting film (mirror film) RF is provided between the light
guide LG2 and the blocking layer BL and between the light guide LG3
and the blocking layer BL. However, due to the same reason as
described in the fourth embodiment, the reflecting film RF is not
necessarily provided.
[0136] As described above, the charged particle beam apparatus
according to the seventh embodiment is the same as the charged
particle beam apparatus 400 according to the fourth embodiment,
except that the optical member OM3 is used instead of the optical
member OM2. Therefore, since the description of other observation
methods and effects are the same as those of the fourth embodiment,
the detailed description thereof will not be repeated.
[0137] In the seventh embodiment, as in the fifth embodiment, the
two light detectors including the light detector 4a and the light
detector 4b may be attached to the upper portion of the chamber 1.
In this case, the light LI1 and the light LI2 can be detected
without rotating the stage 3. Therefore, a dark-field image and a
bright-field image of the sample SAM can be simultaneously
detected.
[0138] In the seventh embodiment, as in the sixth embodiment, the
rotary table 3d that is a part of the stage 3 and includes a
plurality of meshes MS and a plurality of samples SAM may be
provided instead of the top member HLt. In this case, the next
sample SAM can be rapidly observed without replacing the holder HL
or the like.
[0139] The present invention has been described above in detail
based on the embodiments, but is not limited to the embodiments,
and various modifications may be made without departing from the
range of the present invention.
* * * * *