fe-sem basicatc.hitwh.edu.cn/_upload/article/files/1b/0d/27d661264f...hitachi sem’s magnification...
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FE-SEM BASIC
Image
Specimen
Obj Lens
Optical source
Opt
Screen Image Image
Specimen
Specimen
Obj Lens
Electric source
Condenser Lens
SE Detector
C R T
T E M S E M
Scanning
Difference among OM, TEM and SEM
Electric source
Condenser Lens
Deflection Coil
Object Lens
Specimen
Chamber
Vacuum Pump
SE Detector
Amplifier
Deflection Amplifier
Electron Beam
Deflection
Coil
Monitor
1st Anode
2nd Anode
FE Tip
Vacuum Pump
Specimen
Electron Gun
SE
Configuration of a scanning electron microscope
SEM
Scanning Electron Beam of CRT
CRT
DS
Scanning(X)
Scanning(Y)
Magnification :( M)=DS / DD
Specimen
Scanning Electron Beam of SEM
Scanning(X)
Scanning(Y)
Magnifying mechanism in the SEM
DD
Hitachi SEM’s Magnification is base on the size of 4x5 inch film.
(Otherwise CD-SEM is base on the size of Monitor’s Window)
4×5 inch Film
DD
Deflection Coil
DS
Sample
(M)= DS / DD
Magnifying mechanism in the SEM
Specimen Interactions
Electron scatting area
Secondary Electron
(surface features)
Primary Electron Beam (~30kV)
試料
Characteristic X-Ray
(Composition)
Backscattered
Electron
(Topography・Composition )
Cathodeluminescence
(chemical composition )
Specimen absorption
current
Auger electron
(composition of surface layer)
<10nm (the depth of SE
generation)
d
Primary Electron Beam (~30kV)
Auger electron Secondary Electron
BSE
Characteristic
X-Ray
continuous x-ray
Cathode luminescence
Electron Scatting inside of specimen
-
-
-
-
Backscattered
Electron
(internal information) Secondary Electron
(Surface features)
Sample(Metal)
Vacuum
Characteristics of SE and BSE
(How to produce)
100 10,000 1
Energy of Electron (eV)
Qu
an
tity
o
f
Ele
ctr
on
s
(Incident beam energy : 10,000eV)
Secondary Electrons
Backscattered
Electrons
Energy spectrum of the electrons emitted
from a specimen
Electron Scatting inside of specimen
Vacc= 1kV Vacc= 15kV
1μm
Zoom out
20 nm
1μm
20 nm
Specimen:Carbon
Vacc=20kV Vacc=1.0kV
Specimen:16MDRAM Capacitor
Magnification:x50k
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電子ビーム照射部位からの二次電子放出(低加速電圧の場合)
電子ビーム照射部位からの二次電子放出電子ビーム照射部位からの二次電子放出((低加速電圧の場合低加速電圧の場合))
一
Z(10nm)
2次電子発生領域
2次電子(SE1)(試料表面情報)
2次電子(SE2、3)内部情報はなし
最表面の情報を忠実に再現
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一一
Z(10nm)
2次電子発生領域
2次電子(SE1)(試料表面情報)
電子ビーム照射部位からの二次電子放出(高加速電圧の場合)
電子ビーム照射部位からの二次電子放出電子ビーム照射部位からの二次電子放出((高加速電圧の場合高加速電圧の場合))
2次電子
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2次電子(SE2、3)(内部情報含む)
表面情報と内部情報が混在
試料
Image at different Vacc
Electron beam
Second Electron
Specimen
Scanning
θ
Emitted SE amount vary depending on
topography
composition
Potential difference
Electron incident angle and emitted SE amount
SE signal
intensity
Upper section
appears darker
for a large
sphere.
Small particles
often appear
abnormally
bright. Edges appear
abnormally bright.
(Edge effect)
>10μm
Scanning beam
Internal
compositional
information
SE : Secondary electrons only come out of topmost shallow layer
(approx.10nm).
BSE
Review of SEM basic
(Secondary Electron excitation volume)
Sample surface
profile
MonteCalro simulation
Comparison of scattering region of incident electrons (Sample : Si)
Vacc : 10kV Vacc : 1kV
Scanning beam
Sample surface
profile
HA-BSE intensity
compositional/channeling
information
>10μm
1μm
MonteCalro simulation
Comparison of scattering region of incident electrons (Sample : Si)
Vacc : 10kV Vacc : 1kV
Scanning beam HA-BSE
Compositional information
LA-BSE Compositional information
+ topographical information
BSE Internal compositional information
Intensity vary depending on
accelerating voltage.
LA-BSE intensity
compositional/channeling
information
+ topographical information
BSE : Emission depth depends on
accelerating voltage.
Sample : Ni-Al alloy
Review of SEM basic
(BackScattered Electron excitation volume)
Scanning beam
Resolution of SEM
放大
放大
For example: Digital Camera
Resolution of SEM = the minimum recognizable distance between
two particles
unrecognizable recognizable
Resolution of SEM
Wehnelt
Filament
a2
b2 M2=b2/a2
a1
b1 M1=b1/a1
a3
b3
M3=b3/a3
Cross Over Point (d0)
Anode
Electron Beam
Aperture
Specimen
1st Condenser Lens
2nd Condenser Lens
Aperture
Objective Lens
Spot Size (d)
d=d0・M1・ M2・M3
The lens system of a scanning electron microscope
specimen
Vacc
Mag.
Resolution
: Pt particles
: 30kV
: 800kX
: 0.4nm
S-5500
Specimen
Vacc
Mag.
Resolution
: Pt particles
: 15kV
: 220kX
: 1.0nm
S-4800
100nm
Base on
4x5 inch
film
Resolution of SEM
Tungsten SEM
Vacc
V Bias Tungsten SEM Tip Vacc
Vext
Flashing Power
FE SEM Tip
1st Anode
2nd Anode
FE SEM
750μm
ΔV= ~2eV ΔV=~0.2eV Tungsten SEM Tip FE Tip
Energy spread is better
Comparison
Tungsten LaB6 Schottky Cold FE
Electron Size 30μ 10μ 20nm 5nm
Luminance(A/cm3・sr) 106 107 108 109
Energy spread(eV) 2 1.5 0.5~1 0.2~0.5
Cathode Temperature 2500 1800 1700~ room
Vacuum (Pa) 10-4 10-5 10-6 10-7
Life Time of Tip(hr) 50 100 5000 More than 1 year
Range of
use
Low Vaccum
Surface structure observation
WDX/EDX analysis
CL/EBSD analysis
Stable Ip of long time running
High resolution
Low accelerated Voltage
Observation
WDX/EDX analysis
CL/EBSD analysis
Stable Ip of long time running
CD-SEM(On line SEM)
Ultra high resolution
Ultra low accelerated
Voltage Observation
EDX analysis
Signal selection
STEM
Series S-2000 S-3000 S-4300SE/N
CD-SEM
S-4000
S-5000
Resolution
&Max Mag
(for example)
3.0nm/x300k 1.5nm/x500k 0.4nm/x2000k
Object lens type
Primary Beam SE detector
specimen
Primary Beam
Lens
spcimen
SE detector Primary Beam
SE detector
Lens
specimen
Out Lens In Lens Semi-in Lens
Accelerated Voltage(kV)
Out Lens
Semi-in Lens
In lens
S-4300SE S-5200/S-5500 S-4700/S-4800
Re
so
lutio
n (n
m)
Specimen
Object
Lens
+V
+10kV
|FE|=|FB|
FB
電流 I
力
磁界 B
E×B
B FE
FB
E
e
FE
FB
Upper Detector
ExB
Specimen
Upper Detector
Object
Lens
+V
E×B
+10kV
電流 I
力 FB
磁界 B
B FE
FB
E
e
e
FE
FB
ExB
Multi signal detection
SE/BSE signal
Primary Beam
Specimen
Super ExB SED1
BF-STEM APT
(option)
S-4800 signal detected system
SE
BSE
・Surface information
・High resolution
・easy to charge up
・energy :10 -100eV
SE
・composition information
・not easy to charge up
・less edge effect
・energy: depend on Vacc
BSE
SE or SE+BSE-L
Super ExB
SED2
BF-STEM Detector
(option)
Obj lens
Al / W
Wire
SE
BSE
ExB
SE
BSE
ExB
Lens
Specimen
Primary Beam Upper
Detector
SE Mode BSE Mode
Lens
Specimen
Upper
Detector Primary Beam
2μm
SE Mode SE+BSE-L Mode
SE/BSE-L
TFT(Thin Film Transistor) Vacc:2kV Mag:×12K
FIB, no coated
Glass
S-4800
SE Mode SE+BSE-L Mode
500nm Glass
SE/BSE-L
TFT(Thin Film Transistor) Vacc:2kV Mag:×12K
FIB, no coated
S-4800
Vacuum System
离子泵(Ion Pump)
机械泵(Rotary Pump)
(干泵 Dry pump)
油扩散泵(Diffusion Pump)
分子泵(Turbo Molecular
pump)
Vacuum(Pa) Point Hi-SEM FE-SEM
~10-1
10-5~10-8Pa
・可以从大气压开始抽 ・有挥发油(RP) ・ 无挥发油(干泵)
使用 使用
使用
使用
10-3~10-6
・价格底・耐用
・震动少
・有挥发油
・需要前期抽真空装置
・无油干净的真空 ・与DP相比,比较贵 ・需要做一定的减震措施 ・需要前期抽真空装置
~10-10Pa
・可以达到超高真空
・无震动
・需要前期抽真空装置 使用
使用
使用
ガス分子
フラッシング前
FEチップ ガス分子
フラッシング前
FEチップ
フラッシング フラッシング
吸着、吸蔵されたガス分子が完全に除去されている吸着、吸蔵されたガス分子が完全に除去されている吸着、吸蔵されたガス分子が完全に除去されている
The function of Flashing is to reflash the surface of FE tip
Flashing
Flashing
FE Tip Gas
Before Flashing
Remove gas from FE tip
Ie
Time After Flashing
15 min
10%
Flashing
FE Tip FE Tip FE Tip
Flashing necessary
Stable period:4~8hr
END
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