Current Status of NewSUBARUNewSUBARU Storage Ring
Y. Shoji
The total machine time in FY2011 was 2323 hrs,
90% of that of FY2010, including the beam downtime. Fig. 1 shows the breakdown. The beam downtime includes not only the down by a failure, butalso off-beam periods by a beam abort or others dueto the beam instability. The normal user time in thisFY, 1526 hrs, was about 102% of that in FY2010.
Time for machine study and special users was 58%
of that in FY2010. The down time due to themachine trouble was 1.0%, the same level with thatin FY 2010.

Storage Ring Parameters
The machine parameters of the 1.5 GeV storage
ring are listed in Table I. Although the machinecondition remains the same, some of the values arerevised according to the new model calculation.
Table I Main parameters of the NewSUBARU
storage ring in FY2011.
Circumference
118.73 m
Bending lattice typemodified DBA
Number of bending cells 6
Straight sections
4m X 4, 15m X 2
Bending radius
3.22 mInjection energy
1.0 GeV
Maximum energy
1.5 GeV
RF frequency
499.955 MHz
Betatron tune
6.29 (H), 2.23 (V)Momentum compaction factor
0.0014
Electron energy
1.0 GeV 1.5 GeV
RF voltage
100 kV 260 kV
Natural energy spread
0.047% 0.072 %Natural emittance
50 nm 112 nm
Maximum beam current 500 mA

Machine Troubles
The machine troubles in FY2011 are listed inTable II. Fig. 2 shows the rate of some typicalfailures in these six years. The rate of the same
trouble has been decreasing year by year.

Beam Down Case

7

Operation Status
The ring has two user-time operation modes, 1.0
GeV top-up operation mode and 1.5 GeV operation
mode. The basic operation time is 9:00 - 21:00 of
weekdays. Monday is used for machine R&D,
Tuesday is for 1.5 GeV user time, Wednesday andThursday are for 1.0 GeV top-up user time, Friday isfor 1.0 GeV or 1.5 GeV user time. Night period orweekend is used for machine study and user timewith the special mode, single bunch operation andLaser-Compton Gamma ray, if necessary.

1GeV top-up

5

1GeV pile-up

4

acceleration

3
2
1
0

2006 2007 2008 2009 2010 2011

Year

Figure 2: Rate of machine troubles since FY 2000.
The largest loss in this FY, we lost 12 hours,
was the hardware trouble in the radiation safety
PC. We had to stop beam injection because thePC could not save new radiation data.
Another big trouble was a vacuum leak. In July
we identified a slow vacuum leak at BL11 from a
reduction of beam lifetime at 1GeV. We needed
weeks to understand it because the slow leakstopped at 1.5GeV. The leak point was near thephoton absorber. It was fixed immediately after therecognition.

beam down time by machine troubles
24 hrs (1.0%)
machine tuning
348 hrs(15%)
machine study &special user time
425 hrs(18%)

6

Machine Study and Special User Time
Table III shows the list of machine studies in
FY 2011. One special theme, a research related toa production of Laser-Compton backscattering γray and its use, took about 1/3 of the machine
study time as had been in the passed FYs.
Most of the study reports are open to the public
on the home page of NewSUBARU ( http://www.
lasti. u-hyogo. ac. jp/ beam_physics/ NewSUBARU).

user time
1526 hrs(66%)

Accelerator Improvements
The linear lattice model of the ring was
improved. Figure 3 shows the ring parameters of 1/4

Figure 1: Machine time in FY2011.

1

of the ring using the old and the new model. The
new model was based on the measurement of thesteering response. The most serious difference wasthe vertical beta function at the center of the longstraight sections (s=0).
4

βx

20

3

βy

η

2

10

1

DS

SSS

0

Q3
Q4

Q1
Q2

Q2
Q1

Q4
Q3

Q3
Q4

DS

η (m)

β (m)

40

4

Old Lattice Model

30

βx

20

3

βy

η

90

2

10

1

0

5

10

DS

15

s (m)

20

SSS

0

Q3
Q4

Q1
Q2

Q2
Q1

Q4
Q3

Q3
Q4

LSS

QA
QB
QC

0
-10

-1

Injection Efficiency (%)

LSS

-10

QA
QB
QC

0

DS

25

30

-1

Figure 3: The old and the new linear lattice modelfor 1/4 of the ring.

80
70
60
50
40
2011/4The steering response matrix used in the COD
correction system was also improved. The oldmatrix had been the one calculated from the oldmode,l which had worse accuracy especially invertical direction. The new matrices, one for 1GeV
and the other for 1.5GeV, was the results of themeasurement. The iteration process for the COD
correction was improved and became faster.
The topical operational improvement was theraise of the top-up beam current at 1.0 GeV, from
220 mA to 250 mA. Figure 4 shows the history of
the top-up beam current in these 5 years. This wasachieved by better injection efficiency (Figure 5)
and longer beam lifetime (Figure 6). At the best
tuned machine condition we succeeded in 300 mA
top-up operation.
Many machine studies about the injection
process proved the importance of the horizontal
quadrupole matching at the injection. The thin (0.1mm) beam monitor screen was installed to one of the
profile monitors in the beam transport line (L4BT).

bad operatingpoint

New Lattice Model30

2011/6

2011/8 2011/10 2011/12 2012/2

date

2012/4

Figure 5: The improvement of the injection
efficiency with typical undulator gap in FY2011.
1.8

I τ (A hr)

1.6
1.4

vacuum leakat BL1140

It improved the resolution from 1 mm to 0.2 mm(FWHM) and enabled an accurate Q-scanning,which was necessary for the matching. It realized thestable injection with high injection efficiency.
The commissioning of the multi-element
corrector magnets, which were set at both ends ofthe long undulator, brought in the improvement of
the beam lifetime. Not only the excitation of themultipole elements, but also the re-optimization of
the existing magnet parameters made a big progress.
On the other hand, the machine studies in thesesome years using the in-gap sextupole windings set
at 6 invert bending magnets were not successful. It
did improved the beam lifetime, however sacrificing
the injection efficiency

1.2
1
0.8
2011/4

2011/6

2011/8 2011/10 2011/12 2012/2

date

2012/4

Figure 6: The improvement of the beam lifetime at 1
GeV with typical undulator gap in FY2011.
.

2

Table II

Machine troubles in FY2010.

Group
Failure/trouble
beam down time (hr)Operation (software)
RF voltage control program trouble
0.5Miss operation (human error)
1.2
Operation (others)High radiation at intentional beam abort
0.4
beam loss by a beam instabilities
3.7
Trouble of radiation safety interlock system
12.0
Troubles at SPring-8 (delay of starting schedule)
1.8
Vacuum leak at BL11
3.6
Electric power down by a thunder
1.3
Table III

List of machine studies in FY2011. The unit of study time is counted by shifts (typically 12 hrs).

R＆D theme and special user mode
responsible person
Betatron tune feedback system
S. HashimotoHigh Brightness operation
S. Hashimoto
Cancellation of LU effect
S. Hashimoto
Laser-Compton backscattering γ-rays
S. Miyamoto
Commissioning of the new profile monitor port SR5 Corona Graph
Y. ShojiCommissioning of sextupole windings in the invert bends
Y. ShojiTransverse beam matching at the beam injection
Y. ShojiInstability suppression by chromaticity modulation
Y. ShojiDetection of Coherent Synchrotron Radiation
Y. Shoji
Measurement of skew-quadrupole field distribution in the ring
Y. ShojiCommissioning of the multi-element corrector
Y. Shoji
Measurement of amplitude dependent tune shift
Y. Shoji
Trial Shift of 300mA top-up operation
Y. Shoji
Coherent Synchrotron Oscillation Feedback
Y. Shojistudy shift
4
4
1
19
3
3
2
2
4
2
9
1
1
1

250

injection
mismatchbad betatron
tune

200
150

100

2008

Figure 4

2009vacuum failure
at BL11300

bad injection
efficiency

good injection
efficiency (80%)

bad injection
efficiency
vacuumreplacement
at #6 & #1 cells

Top-up Beam Current (mA)

250mA top-up start
350

year

2010

2011

History of the top-up beam current of NewSUBARU since 2007.

3

2012

B
Beamlines
Takeo Wattanabe and Hirroo Kinoshita
Ceenter for EUV
VL, LASTI, Unniversity of Hyyogo
Total nnine beamlinnes are opperating in the
NewSUBARUU synchrotroon facility. F
Four beamlinees of
BL01, BL03,, BL06 and BL
L11 were consstructed until 1999.
Three beamliines of BL07, BL09 and BL
L10 were starteed theoperation fromm 2000.
BL03B beamlinebbrannched from thhe BL03 beammline
propose for the usage of the EUVL (eextreme ultravviolet
lithography) microscope for the EUV
VL finished mask
inspection.
BL09B beeamline brancched from BL009 beamline fo
for theusage of the usage of the E
EUV interfereence lithograpphy toevaluate. Annd BL09C beeamline brancched from BL
L09B

beaamline for the usage of the tthickness meaasurement of thhecarrbon contaminnation originaated to the reesist outgassinng
durring the EUV exposure.
BL02 beamliine was consttructed for thee usage of LIG
GA
in 22003.
BL05 beammline was connstracted in response to ademmand in the inndustrial world, that is enhaancement of thheanaalysis abilityy in the soft X-ray reggion with thhedevvelopment of nnanotechnologgy.
The arrangem
ment of the beeamlines in thee NewSUBAR
RU
synnchrotron radiation facility isi shown in Fiig.1.

Fiig. 1 Beamlinee arrangement in NewSUBA
ARU.

I. BL01
BL01 is a beamline forr research annd developingg newlight sourc es. This be amline is oneoof two longstrraight sectionn on NewSUUBARU. Opptical klystroon
waas installed att this straightt section. Uppstream side of4

storage ring tunnel was constructed in 2004 for
gamma-ray irradiation experiments. Specificationsof this gamma-ray source are listed in Table 1.

this beamline (BL01B) is intended to be used forvisible and infrared light generated from FEL or SR.
Downstream side of this beamline (BL01A) is used
for laser Compton scattering gamma-rays source.
Gamma-ray beamline hutch just outside of theTable 1. Specification of BL01 gamma beam
CO2 laser
Gamma energy : 1.7 - 4 MeV
Gamma flux* : 9 x106 γ/s
10.52 μm
: 6 x105 γ/s (1.5-1.7 MeV)
5W
(with 3mmφ collimator)
Gamma energy : 17 - 40 MeV
Nd laser
Gamma flux* : 7.5 x106 γ/s
1.064 μm
: 3 x105 γ/s (15-17 MeV)
0.532 μm(with 3mmφ collimator)
5W*Electron beam energy : 1-1.5 GeV*Electron beam current : 250 mA
gamma-ray beam divergence : 0.5 mrad
II. BL02
x-ray mirrors (plane and cylindrical mirror) and Be film
filters. The horizontal angle of the outgoing SR could beobtained up to 12.5 mrad, which corresponds to thehorizontal size of 220 mm (A4 horizontal size) at the
exposure position. The second characteristic performanceof the beamline is the high efficiency differential pumping
system. This was necessary for maintain the vacuum
difference between the storage ring (<10-9 Pa) and theend-station (<10-9 Pa) at which gasses for substrate coolingwill be introduced in the exposure apparatus.
The flexibility for the shapes and functions of
microstructure will be enlarged by achieving 3D
microfabrication process using multi step exposure atvarious configuration between x-ray mask and substrates.
The relative positions between x-ray mask and substrates,
tilt and rotation angle to the SR incident direction can be
moved simultaneously during SR exposure using 5 axis
stages. The movement of each axis is controlled by the PC
in terms of the scanning speeds, scanning length, andrepetition number. In order to decrease the heat load ofsample substrate suffered during SR irradiation helium
introduction and substrate cooling mechanism were alse
equipped. Specification of spectrometer is listed in Table 2.

The LIGA (abbreviated name of Lithogaphic,
Galvanoformung and Abformung) process which consistsfrom deep x-ray lithography, electroforming, and molding
process is one of the promising candidates for such 3D
micofabrication. More than hundreds aspect ratio for
microstructure can be attained by the usa of the higher
energy x-rays (4-15 keV) from synchrotron radiation (SR)with deeper penetration depth to the photosensitive resist.
In this system we have succeeded to enlarged the exposurearea up to A4 size and the fabrication dimension from
submicron to millimeter by varying the energy of the x-ray
source in accordance with the size of desired microparts.
Micostructure with high aspect ratio over several hundreds
will bi achieved using the x-rays over 10 keV since highenergy x-ray has deep penetration depth to thephoto-sensitive resist materials. Whereas, in the case oflithography for low energy x-rays from 1 keV to 2 keV,submicron structures with high aspect ratio will beachieved using the x-rays mask with precise line-width andthinner absorber, since low energy x-rays has low
penetration depth. Based on this principle, the beamilne for
x-ray exposure have constructed with continuous
selectivity of x-rays frpm 100 eV to 15 keV by using theTable 2. Specification of the LIGA exposure system
OpticsPlane and cylindrical mirror, Be filters
Exposure energy
100 - 2 keV, and 4 – 15 keV
Exposure method
Proximity and multi step exposure
Wafer size
A4 or 8 inch
Exposure area
230 mm(H) ×300 mm(V)
Exposure environment< 1 atm (He-gas)

5III. BL03
BL03 is a beamline for the developing the next
generation lithographic technology so called extreme
ultraviolet lithography (EUVL). The exposure tool isinstalled at the end station. Using this exposure tool, theresearch and development of the next generation
lithography such as the less than 70 nm node is going on
process. The exposure wavelength is 13.5 nm.
The semiconductor industry plays a very important rolein the information technology (IT). In 2006, 256 Gbit
DRAM with a gate length of 70 nm will be demanded in
the IT industry. The extreme ultraviolet lithography(EUVL) is a promise technology for fabricating a finepattern less than 70 nm. To meet this schedule, thistechnology has to be developed in the pilot line until 2004.
As for the practical use, it is very important that both toachieve large exposure area and to fabricate fine patterns.
Therefore, at Himeji Institute of Technology, large
exposure field EUV camera consists of three asphericalmirrors was developed. First in the world, we fabricated 60
nm line and space pattern in the large exposure area of 10
mm×10 mm on a wafer. Furthermore, BL03B beamline
branches from the BL03 beamline propose for the usage of
the EUVL microscope for the EUVL finished mask
inspection.

Table 3. Spectification of the exposure tool (ETS-1)
Imaging optics
Three aspherical mirrors
Exposure wavelength13.5 nm
Numerical aperture
0.1
Demagnification
1/5
Resolution
60 nm
Depth of focus
0.9 µmExposure area (static)
30 mm×1 mm
Exposure area (scanning)
30 mm×28 mm
Mask size
4 inch, 8 inch, and ULE 6025
Wafer size
8 inchExposure environment
In vacuum

IV. BL05
BL05 was constructed in response to a demand in theindustrial world, that is enhancement of the analysis ability
in the soft x-ray region with the development of
nanotechnology. BL05 consists of two branch lines for use
in the wide range from 50 eV to 4000 eV. BL05A and
BL05B are designed to cover the energy range of
1300-4000 eV and 50-1300 eV, respectively. The incident
beam from the bending magnet is provided for two branchlines through different windows of a mask. Therefore,
these two branch lines can be employed simultaneously.

1) The double crystal monochromator was installed at
the BL05A. InSb crystals and Si crystals are prepared for a
double-crystal monochromator. Toroidal mirrors are used
as a pre-mirror and a focusing mirror of BL05A. XAFS
measurement in the total electron yield mode andfluorescence XAFS measurement using SSD (SII Vortex)
can be performed. The fluorescence XAFS spectra can bemeasured for samples at the end station filled with He gas.

Table 4. Monochromator specification
Monochromator
Double crystal monochromator
Monochromator crystals
InSb(111), Si(111)Energy range
1300-4000 eV
E/⊿E=3000
Resolution
on BL05B. The optical system consists of a first mirror(M0), a second mirror (M1), an entrance slit (S1), a
pre-mirror (M2), and three kinds of plane grating (G), an
exit slit (S2) and a focusing mirror (M3). The including2) The constant-deviation monochromator consisting of ademagnifying spherical mirror and a varied-line-spacing
plane grating (VLSPG), which can provide high resolution,
simple wavelength scanning with fixed slits, was mounted

6

photoelectron spectrum can be measured using sphericalelectron analyzer (VG Sienta, R3000) in an ultra
high-vacuum chamber. The chambers can be replaced byeach other within 1 hour.

angle of the monochromator is 175°. Two measurement
chambers are prepared at the end station of BL05B. The
XAFS spectra in the total electron yield mode andfluorescence XAFS spectra using SDD (EDAX) can bemeasured in a high vacuum chamber. In addition, theMonochromator
Grating
Energy range
Resolution

Table 5. Monochromator specification
Varied-line-spacing plane grating monochromator
100 l/mm, 300 l/mm, 800 mm/l
50-1300 eV
E/⊿E=3000

V. BL06
BL06 has been mainly developed for irradiation
experiments such as photochemical reaction, SR-CVD,
photo-etching, surface modification. The white radiation
beam from bending magnet is introduced to the sample
stage using a pair of mirror, whose incident angle was 3°.
The SR at BL06 sample stage had a continuous spectrum
from IR to soft x-ray, which was lower than 1 keV. A

differential pumping system can be utilized forexperiments in a gas atmosphere, which is difficult in thesoft x-ray region. A sample holder can install four pieces ofsamples at a time. By using heater set in the sample holder,
the sample can be heated from room temperature to 220C.
The temperature of sample is monitored using a Cr-Al
thermocouple mounted on the sample holder.

VI. BL07A and BL07B
This beamline was designed for the development of
new materials by SR technology. This beamline consists of
two branch lines, which are provided with an incident
beam from a 3-m undulator by switching the first mirror.
One of them is a high photon-flux beamline with amultilayered-mirror monochromator for the study of
SR-process (BL07A) and another is a high-resolution
beamline with a varied line spacing grating
monochromator for the evaluation of nano-structure
characteristics by SR-spectroscopy (BL07B). The usefulrange of emitted photons from 50 to 800 eV is covered atboth beamlines. The light source of BL07 is a 3-m lengthplanar undulator, which consists of 29 sets of permanent
magnets, a period length of which is 76 mm. The incident
beam from the undulator is provided for two branch lines
by translational switching of first mirror.
Energyrange(eV)Material

50-60
60-95

Mo/Si

90-140140-194
190-400
400-560

Mo/B4C
Ni/C

1) BL07A
The multilayered-mirror (MLM) monochromator,
which has high reflectivity in the soft X-ray region, wasinstalled at the BL07A. It consists of a switching mirror
chamber, a slit chamber, a MLM monochromator, a filter
chamber and a reaction chamber. To obtain a large photon
flux, we decided to use only first mirror (switching mirror),M0, for focusing. The MLM monochromator is designed tocover an energy range of up to about 800 eV by
combination of three kinds of mirror pairs with 4 kinds offilter. The flux deliver by this design is estimated to be
between a maximum of 1017 photons/s at 95 eV and aminimum 21014 photons/s at 300 eV for a 500 mA ring
current.

Table 6. Summary of BL07A.
Multilayer mirror
spacing
Thickness number of
Ratio
layers
20 nm
11 nm
5 nm

0.8

20

0.5

25

0.5

60

550-800

7E/E

Filtermaterial thickness
Al

100 nm

None



Ag

100 nmCr

500 nmNi

500 nm

6.2 %
3.3 %
2.5 %

focusing mirror (M2). The monochromator is designed tocover the energy range 50-800 eV with three gratings, ofwhich including angle are 168. The VLSPG has been wellknown to obtain high resolution in extreme ultraviolet
region by diminishing various kinds of aberration. The
total resolving power about 3000 can be realized in thewhole energy region.

2) BL07B
The constant-deviation monochromator consisting of ademagnifying spherical mirror and varied line spacing
plane grating (VLSPG), which can provide to highresolution, simple wavelength scanning with fixed slits,
was mounted on BL07B. The optical system consists of afirst mirror (M0), a entrance slit (S1), a premirror (M1),and three kinds of plane grating (G), an exit slit (S2) and a

Table 7. Monocromator specification
Mount type
Hettrick-Underwood type
Grating G1, G2, G3
Plane VLS (600 l/mm, 1200 l/mm, 2400 l/mm)
Energy range
50-150 eV, 150 – 300 eV, 300-800 eVResolving power (E/ΔE)～3000

VII. BL9A purpose of this beamline is studies on a soft x-ray
interferometry or a holographic exposure experiment withmaking use of highly brilliant and coherent photon beams
radiated from 11 m long undulator in NewSUBARU.
BL09 consists of M0 mirror, M1 mirror, G grating andM2 and M3 mirror. M0 and M3 mirrors are used forhorizontal deflection and beam convergence, M1 is usedfor vertical beam convergence at the exit slit, and M2 isused for vertical deflection and beam convergence. A
monochromator is constructed by M1 and a plane grating.
The maximum acceptance of the undulator beam is 0.64
mrad in horizontal and 0.27 mrad in vertical. The

acceptance can be restricted by 4-jaw slits equipped at
upstream of the M0 mirror.
BL09B beamline branched from BL09 beamline for theusage of the EUV interference lithography for theevaluation of the exposure characteristics of EUV resist.
Coherence length of 1 mm at the resist exposure position
was achieved using BL09B beamilne. And BL09C
beamline branched from BL09B beamline for the usage ofthe thickness measurement of the carbon contamination
originated to the resist outgassing during the EUV
exposure.

Table 8. Monochromator specification
Mount type
Hettrick-Underwood type
Grating
Plane VLS (900 l/mm)
Energy range
50 – 600 eVResolving power (E/ΔE)～3000

VIII. BL10
BL10 is for the global use in the Himeji Institute ofTechnology. M0 mirror is used for horizontal deflection andbeam convergence, M1 is used for vertical beam
convergence at the exit slit, and M2 is used for verticaldeflection and beam convergence. A monochromator isconstructed by M1 and a plane grating. At the beginning,the multiplayers reflectiveity measurement was carried out
at this beamline. The characteristics of this beamline andthe result of the Mo/Si multiplayers measurement are
carried out for the development of the EUVL mask
techmology.
BL10 utilizes a monochromator of the varied line

spacing plane grating monochromator (VLS-PGM). Theline density of the monochromator in central region of thegrating is 600 lines/mm. The reflectometer is a two axis
vacuum goniometer using two Huber goniometers. One
axis carries the sample, which may for examplee be amirror at the center of the reflectometer vacuum tank(-motion). The other (-motion) carries the detector on arotating arm. In addition there are through-cacuum linear
motions to translate the sample in two orthogonal directions(x,y). All motors are controlled by computer. The sample
itself is mounted on a kinematic holder. The controlstage
monochromator rotation, and data analysis were program

8

using LABVIEW software. The reflectivity result obtainedat BL10 has a good agreement with that at LBNL.

Table 9. Monochromator specification
Mount type
Hettrick-Underwood type
Grating
Plane VLS (600 l/mm)
Energy range
50 – 600 eVResolving power (E/ΔE)～1000

IX. BL11
A beam line BL11 is constructed for exposure Hard
X-ray Lithography (DXL) in the LIGA (German acronym
for Lithographite Galvanoformung and Abformung)process. LIGA process, that utilizes a useful industrial
application of SR, is one of the promising technologies forfabrication of extremely tall three-dimensional
microstructures with a large aspect ratio. This process wasinvented at the Institut Fur Mikrostrukturtechnik (IMT) of
the Karlstuhe Nuclear Center (KfK) in 1980.
Microstructures with height of over a few hundreds µm
have been widely applied to various fields such as
micro-mechanics, micro-optics, sensor and actuator
technology, chemical, medical and biological engineering,and so on. This beam line was designed by the criteria ;photon energy range 4 keV to 6 keV, a beam spot size on
the exposure stage  505 mm2, a density of total
irradiated photons  1011 photons/cm2. BL11 of anabsorber chamber, a first-mirror chamber (M1), a
second-mirror chamber (M2), a 4-way slit chamber, a Be
window chamber, and an exposure chamber. The second
pre-mirror is bent elliptically using a bending mechanism.

Fine bending adjustment of the M2 mirror can be made in
the UHV by the pulse motor. The LIGA process needs thephoton energies of 3 keV to 6 keV, the optics of a LIGA
beam line generally employ a Pt monolayered-mirror anda Be window, which cuts off low-energy photons. The
reflectivity of a Pt-coated mirror is about 55 % in therange of photon energy from 2 keV to 4 keV, however, it
drops to 30 % at the photon energy of 6 keV. Therefore,
new materials with a high reflectivity must to be found for
Deep X-ray lithography (DXL) in this energy range. We
propose the use of a Ni/W/C multilayered-mirror with agraded d-spacing in the range of photon energy from 3 eV
to 6 keV. The calculated reflectivity of the Ni/W/C
multilayered-mirror is higher than 56 % at the photon
energy of 6 keV with a glazing incident angle of 0.8
degrees, and photons that have higher photon energy than
6 keV can be removed A 200 µm-thick beryllium (Be)window in a Be window chamber is used to separate theultra-high vacuum part from the low vacuum part and to
cut off low-energy photons.

Table 10. Specification of the LIGA exposure system
Exposure method
Proximity exposure
Wafer size
4 inch50 mm(H)×80 mm(V)
Exposure area
Exposure environment< 1atm (He-gas)

9